TABLES FOR A. LIVERSIDGE LIBRARY OF THE UNIVERSITY OF CALIFORNIA. GIFT OF .PROF. w.B. RISING Class TABLES FOR QUALITATIVE CHEMICAL ANALYSIS ARRANGED FOR THE USE OF STUDENTS BY A. LIVEESIDGE &.A., LL.D., F.R.S. HON. F.R.S.E., ASSOCIATE OF THE ROYAL SCHOOL OF MINES, LONDON PROFESSOR OF CHEMISTRY IN THE UNIVERSITY OF SYDNEY SECOND EDITION . Eontron MACMILLAN AND CO., LIMITED 1904 ALL RIGHTS RESERVED INTRODUCTION. In these tables, primarily prepared for the use of my own students, I have made an attempt to combine some of the advantages of Quantitative methods with the processes of Qualitative Analysis. It is assumed that the student using these tables has been through a preliminary course of practical instruction, including such matters as glass working, the use of the blowpipe, an instrument far too much neglected nowadays, the preparation of the gases and of certain salts, etc. The experiments upon the preparation of gases, salts, etc., should also be carried out upon Quantitative methods, i.e., the quantities of the materials necessary for their preparation should be calculated and weighed out or measured by the student himself. In the case of gases, he should also be required to measure the capacity of the gas jars intended to be filled and to correct their contents for tempera- ture and pressure. This part of the experimental work will thereby afford far better training, be more instructive and more interesting to the beginner than the usual routine arithmetical questions upon the preparation of given volumes of gases and the correction for temperature and pressure. The educational value of Qualitative Analysis. Of late it has been usual to condemn instruction in Qualitative Analysis, and to allege that it is a waste of time. This may be true if the student is allowed to go on mechanically testing mixture after mixture and is not required to give evidence that he understands what he is doing ; to this end he should be frequently questioned as to the reasons for making any given experiment, and the chemical reactions it is intended to bring about. If the student be required to do his qualitative work intelligently, the time given to it is well spent ; there is probably more scientific training and discipline involved in it than in ordinary Quantitative Analysis, and if properly taught it is of great educational value. The preliminary tests applied to complex mixtures are especially useful in training the observing and reasoning powers, on account of the way in which reactions are modified or interfered with when several substances are present. It is not possible for everyone who requires some knowledge of practical chemistry to devote time to such matters as the verification of the laws of 237403 INTRODUCTION combination, the preparation and the purification of materials or to undertake an original research, but many, e.g., medical students, require to have some knowledge of Qualitative Analysis ; chemical and mining students need a larger and better knowledge, and it is desirable that they should be taught this in an instructive manner and not as mere test-tubing. It is, of course, not necessary for every student to work through the reactions for all the substances given in these tables ; typical ones can be selected according to circumstances, e.g. the medical student need not necessarily work through the reactions of rare earths. Theory of Qualitative Analysis. It is assumed that the student will be taught the principles of analysis and how to use these tables, and that he will not be left to struggle through them unaided ; it is for this reason and because the book is intended for bench use that equations and the usual more or less lengthy explanations are omitted. The directions are made as brief as possible, for students when engaged in practical work have usually neither the time nor the inclination to wade through more or less lengthy descriptions of the methods of procedure. In this laboratory the principal explanations are given in the form of lecturettes and demonstrations of fifteen or twenty minutes before the practical exercises ; the class also meets once a week for one hour's tutorial instruction in the theory of qualitative analysis, chemical equations, calculations and similar matters, and there is a written examination upon the work at the end of the term, as well as practical and theoretical examina- tions at the end of the year. Weighing and Measuring. By requiring the student to work throughout with weighed or measured quantities, it is necessary that he should be shown, unless he is already familiar with them, how to use the balance, burette, measuring flasks and pipettes ; the small amount of extra time necessary for this will, however, be well spent. The quantity of substance to be examined can either be weighed out separately by each student, or students can take it in turns to weigh out and divide the portions for a group of students. The balance used need not be an expensive one, very good chemical balances, weighing to a milligram, can now be obtained for less than 3O/- ; if the balance available is not sufficiently sensitive for the smaller weights, larger quantities can be weighed out, placed on glass or glazed paper and divided by a spatula into approximately equal parts, just as powders are sometimes divided by pharmacists ; although this would not be quite so satisfactory, it would be a great improvement upon the usual method of shaking an indefinite quantity out of a bottle. INTRODUCTION In applying the colour tests for alkaloids, a weighed quantity, say a milligram, should be divided by a spatula into the requisite number of approximately equal portions, as it is quite unnecessary to weigh the fractions of a mgin. Although a mgm. may be thought to be a small amount to be divided into five or even more portions, yet as the alkaloids are of comparatively low density there is no practical difficulty in obtaining the reactions with such quantities ; in poisoning cases the amount of alkaloid to be sought for is usually small, it is therefore well for the student to acquire skill in working with small quantities. The amounts of material and reagents recommended have been carefully tested and proved to be ample for the purpose, and in some instances even smaller quantities than those mentioned would be sufficient. The amounts prescribed are not given in proportion to the equivalent or molecular weights of the substances, because the difference between them and those recommended would not, as a rule, be appreciable. The quantities to be used are given to promote accuracy of work, to save time, and to prevent waste of chemicals ; usually an excessive quantity of the substance to be tested is used and then ' ' drowned ' ' in acids and reagents, which means great waste of material and a greater and more deplorable waste of time in filtering large volumes of solution and in washing bulky and unwieldy precipitates. Further, by causing students to weigh and measure out the materials, they will acquire during their qualitative work a knowledge of the use of the balance and of volumetric apparatus which will be a useful introduction to quantitative determinations. Graduated Test Tubes. For simple tests, small test tubes of ^ or y% inch diameter are much better than the larger sizes, for their contents can be boiled and otherwise treated so much more quickly. It is as well to have these graduated into c.c. ; the student should do this for himself by running in water from a burette and marking the c.c. by gummed paper bands, with paint, or by hydrofluoric acid ink, etc. ; one burette will be sufficient for several students. Equivalent Solutions. The acids and solutions used should be "equivalent" ones, so that even the ordinary precipitation and other tests can with the use of graduated test tubes be carried out in a more or less quantitative manner. A table of Equivalent Solutions is given on page 115. When an ''excess " of a reagent is to be added, the beginner will be able to carry out the operation much less clumsily than he usually does with ungraduated test tubes. INTRODUCTION Instead of being told to add " a few drops," which to the ordinary beginner means anything from 5 or 6 drops to several c.c., he should be required to add a definite number of drops carefully counted. It is usually the best plan to deliver the drops from the end of a glass rod, although in careless hands this may lead to the reagents being contaminated, from the unrinsed rods being dipped into other bottles. Dropping-bottles and bottles with pipette stoppers are very useful for certain reagents, but they cannot well be used for all of them. Mixtures. The mixtures for analysis should, as far as possible, be made up in terms of the molecular weights of the constituents, and in proportions according to the difficulty of detecting them and not haphazard, as is too often the case. After a little experience with the usual artificial laboratory mixtures, minerals and other natural mixtures should be given wherever possible, as they usually present greater difficulties and are of more educational value. Preliminary Tests. Most common substances can be detected by the preliminary tests, and a student should be required to learn to do so as far as possible, he then, if provided with a blowpipe, a candle, a few accessories and reagents, is almost independent of a laboratory, i.e., as far as ordinary minerals and common substances are concerned ; the power to work with few and simple materials is an immense advantage to the explorer and miner. If the student finds a substance by the wet processes, which he has failed to detect by the preliminary tests, he should be required to repeat the preliminary tests until he does find it, i.e., if it is possible to do so, if impossible he should be required to state in his note book the probable reasons why it cannot be so detected, especially if there be anything present which interferes with or masks the usual reactions of the substance in question. Blowpipe Tests. For the blowpipe tests, a portion of the substance not larger than a pin's head is usually ample ; beginners often fail to get the proper results because they use too much of the substance, they often use such excessive quantities as to almost need a crucible and a furnace instead of a mouth blowpipe. Students should be carefully shown how to make a suitable cavity in charcoal for blowpipe experiments, how to make a proper platinum wire ring (not an irregular loop) for borax beads, how to mix fluxes, and other similar operations, and not be left to do them in the usual slovenly way. Note Books. Students should be required to enter the date and hour they commence and finish a given piece of work, and to enter up a table of INTRODUCTION contents at the beginning of the note book, so that the progress and range of their work can be seen and kept in view both by the teacher and student. The entries should as far as possible be initialled by the instructor from day to day and not at intervals of a week or so. I am only too well aware of the inherent defects in these, in common with other similar analytical tables, and mistakes may also have crept in unawares, but I hope that teachers of chemistry into whose hands they come will not only give the quantitative methods described a fair test, but improve upon them. A. UVERSIDGE. The University of Sydney. December, \ ERRATA. Page 15, line 25, for Fe 3 "(Fe"'Cy 6 ) 3 read Fe 3 "(Fe'"Cy 6 ) 2 . ,, 18, lines 2 and 4 from foot, for K s Co(NO 2 ) 3 read K 3 Co(NO 2 ) 6 18, last line, for Ni(OH) 3 read Ni(OH) 2 . ,, 30, line 8 from foot, for ZrS 2 O 3 read Th(OH) 4 and S. ,, 30, line 12, for ZrS 2 O 3 read Zr(OH) 4 and S. ,, 30, line 6 from foot, for Titanum read Titanium. ,, 37, line 8 from foot, for CuSO 4 read Cu 2 SO 4 . ,, no, line 9, for 'i gm. read i gm. REACTIONS OF THE METALS. GROUP I. SILVER, LEAD AND MERCURY. Silver. Ag, 107-12. DRY TESTS. i. Blowpipe. Heat about "01 gm. AgNO., on charcoal with Na. 2 CO 3 : hard white malleable metallic beads. Diss. beads in dil. HNO 3 , add NaCl sol. : white AgCl. 2. Match test. Use about '01 gm. AgNO 3 : Ag beads. WET TESTS. Diss. 'i gm. of AgNO 3 in 10 c.c. aq. and use i c.c. for each test. HC1 : white curdy ppt. of AgCl, insol. in dil. acids, soluble in NH 4 OH, KCN, Na,S,O 3 , also in strong HC1, NaCl sol. etc. The AgCl darkens on exposure to light. SH, : black Ag,S, insol. in NH 4 SH. NH 4 OH : grey AgOH. (Note. Very sol. in excess. Apply the NH 4 OH from the end of a thin glass rod to the side of the test tube just above' the AgNO 3 sol. and let the NH 4 OH trickle down to the AgNO 3 sol.) NaOH : grey brown AgOH, insol. in excess. Na 2 C0 3 : white Ag 2 CO 3 , insol. in excess. KI : pale yellow Agl, insol. in dil. HNO 3 and almost insol. in NH 4 OH. KBr : yellowish AgBr, insol. in dil. HNO 3 , difficultly sol. in NH 4 OH, readily in KCy, Na. 2 S,O 3 , and KI. KCy : white curdy AgCy, readily sol. in an excess, in NH 4 OH, and in Na 2 S 2 O 3 but insol. in dil. HNO 3 ; on ignition : metallic silver. K 2 Cr0 4 : dark red Ag 2 Cr.O 4 . Copper foil : ppt. of grey metallic Ag ; rub with glass rod : metallic lustre. Lead. Pb, 205-35. DRY TESTS i. Blowpipe. Heat about 'or gm. Pb2NO 3 on char, in the reducing flame : soft, greyish metallic beads which mark paper. In the oxidising flame an incrustation is formed, reddish brown when hot, yellow when cold. 2. Match test. Use about '02 gm. Pb2NO 3 : Pb beads. 3. Film test : black. WET TESTS. Diss. 0*2 gm. of lead acetate, in 7 c.c. aq. (if cloudy add one drop of acetic acid). 10 MERCURY HC1 : white crystalline PbCl 2 , insol. in NH 4 OH, sol. in hot aq., rede- posited on cooling. Filter and pass SH 2 through the cold sol. : a black ppt. of PbS which shows that PbCl 2 is somewhat soluble in the cold, or add KI sol. : yellow PbI 2 . SH 2 in the presence of HC1 : black PbS, but if too much HC1 be present a reddish ppt. of PbS,PbCl 2 comes down. H 2 S0 4 : white PbSO 4 , soluble in ammonium acetate, in am. tartrate, in excess of NH 4 OH and in Na 2 S 2 O 3 . NH 4 OH : white ppt. (basic salt), which crystallizes out on cooling, insol. in excess. NaOH : white PbO 2 H 2 , sol. in excess. KI : yellow ppt. of PbI 2 sol. in excess and in hot aq. K 2 Cr0 4 : yellow PbCrO 4 , sol. in HNO 3 and in NaOH. Mercury. Kg, 198-5. DRY TESTS. i. Blowpipe. On charcoal, volatilizes. 2. Ignition tube, (a) Heated in a dry tube, salts of mercury yield a sublimate, (b] Heated in a tube with soda-lime or char, powder and Na 2 CO 3 : metallic globules or mirror, insoluble in HC1, soluble in hot HNO 3 and in H 2 SO 4 . 3. Film test : (a) Metallic mirror MERCUROUS SALTS. WET TESTS. Diss. '2gm. HgNO 3 in 10 c.c. aq. and a few drops dil. HN0 8 . HC1 : white ppt. of HgCl, blackened by NH 4 OH. SH 2 : black HgS mixed with Hg, sol- uble in aq. regia, insol. in NH 4 SH. NH 4 OH : black ppt.* NaOH : dark grey ppt. Hg 2 O. Na 2 C0 3 : white ppt. ; darkens Kl : green Hgl, sol. in excess of KI. K 2 Cr 2 7 : red ppt. SnCl 2 : white HgCl, on warming : grey metallic Hg. (b) with SH 2 : black. MERCURIC SALTS. WET TESTS. Diss. '2 gm. HgCl 2 in loc.c. aq : no ppt. : white, yellow and red mixtures of HgCl 2 and HgS, finally black HgS. : white ppt. of (NH 2 .Hg"Cl). : yellow HgO. : brown ppt. : yellow changing to red HgI 2 , sol. in excess of KI and of HgCl 2 . : no ppt. but a yellow ppt. with K 2 CrO 4 . : white ppt. of HgCl, grey with an excess of SnCl 2 . * Probably a mixture of mercuric am. nitrate and free Hg. BISMUTH AND COPPER II Acidulate slightly with HC1 and immerse a strip of bright copper foil : grey deposit of metallic Hg, from both the HgNO 3 and HgCl 2 sols., rub to collect into globules and to show metallic lustre. GROUP HA. MERCURY, L,EAD, BISMUTH, COPPER AND CADMIUM. Bismuth- Bi, 206-9. DRY TESTS. i. Blowpipe. Heat '02 gm. Bi. 2 O 3 on charcoal in inner flame with Na. 2 CO 3 and KCy : brittle reddish metallic beads and orange incrustation, but yellow on cooling. 2. Ignition tube. Heated in tube, Bi salts decompose and leave Bi. 2 O 3 , orange when hot, yellow when cold. 3. Match test. Use about '01 gm. Bi 2 O 3 : Bi beads. WET TESTS. Diss. *i gm. Bi(NO 3 ) 3 in 7 c.c. aq., or '2 gm. Bi 2 O 3 in 5 c.c. dil. HC1, then dilute with aq. to 7 c.c. HC1 : no ppt., but on diluting very largely with aq., white BiOCl comes down, insol. in KOH and in KHC 4 H 4 O (5 (Hyd. pot. tartrate). SH. 2 : dark brown ppt. of Bi 2 S 3 , insol. in NaOH, sol. in HNO 8 . NH 4 OH : white Bi (OH) 3 , insol. in excess. NaOH : white Bi(OH) 3 , insol. in excess. KI : (0*1% soln.) : brown BiI 3 , very sol. in excess. KCy : white Bi(Cy) ;1> insol. in excess. K 2 Cr 2 7 : yellow Bi 2 (CrO 4 ) 3 . Copper. Cu, ea-i. DRY TESTS. i. Blowpipe. Mix about '02 gm. CuO with Na. 2 CO 3 and KCy, heat on charcoal in reducing flame : red malleable metallic particles. 2. Match test : Cu beads. 3. Borax bead : green, hot ; blue, cold ; red in reducing flame. 4. Flame test : flame, coloured green ; halogen compounds of Cu, e.g. , CuCl 2 , give a vivid blue. A. CUPROUS COMPOUNDS. WET TESTS. Dissolve o'i gm. Cu 2 Cl. 2 in 2 c.c. HC1. H 2 : white Cu 2 Cl 2 , changes to green CuCl 2 , which is soluble. KOH : yellow ppt. of CuOH, which absorbs O and becomes black Cu(OH) 2 . B CUPRIC % COMPOUNDS. WET TESTS. Diss. 0*2 gm. CuSO 4 in loc.c. aq., use i c.c. for each test. HC1 : no ppt. SH 2 : black CuS, nearly insol. in NH 4 SH and NaOH, sol. in strong HNO ;< NH 4 OH : pale blue ppt, of basic salt, CuSO 4 .Cu(OH) 2 , sol. in excess to a deep blue sol. 12 CADMIUM AND ARSENIC NaOH : CuO 2 H 2 , .cupric hydroxide, turns black on boiling : CuO, but if substances like grape sugar, tartaric acid, tartrates, urea, are present, a deep blue solution forms, from which on boiling red Cu 2 O is precipitated. Na 2 C0 3 : greenish blue basic carbonate, on boiling : black CuO or 3CuO,H 2 O. K 4 Fc(Cy) 6 : chocolate-coloured ppt. of cupric ferrocyanide, Cu. 2 FeCy 6 . KCy : greenish Cu(Cy) 2 , sol. in excess. [NOTE. SH 2 does not ppt. Cu from this soln. See Cd.] Metallic Zn or Fe ppts. copper from solution as a reddish powder, rub : bright copper particles. Cadmium. Cd, 111-6. DRY TKSTS. i. Blowpipe. Mix about '02 gm. CdSO 4 with Na 2 CO 8 and KCy, and heat on charcoal in inner flame : reddish brown incrustation of CdO. 2. Film test : black, yellow with SH 2 sol. WET TKSTS. Diss. 'I gm. of CdSO 4 in 5 c.c. of aq. SH 2 and 2 drops of HC1 : yellow CdS, insol. in TaOH, NH 4 SH, KCy, and in (NH 4 ) 2 CO 3 ; sol. in hot dil. HC1, HNO 3 and H 2 SO 4 . NH 4 OH : white ppt. of Cd(OH) 2 sol. in excess. NaOH : white ppt. of Cd(OH) 2 insol. in excess. NH 4 SH : yellow ppt. of CdS. KCy : white CdCy 2 , sol. in excess ; SH 2 ppts. CdS from this sol. (See Copper, p. u.) GROUP HE. ARSENIC, ANTIMONY AND TIN. Arsenic. As, 74-s DRY TESTS. i. Blowpipe. Mix with Na 2 CO 3 and heat on charcoal : white incrustation of As 2 O 3 and garlic odour. 2. Ignition tube, (a) Heated in a roasting tube As and arsenical com- pounds give a sublimate of As 2 O 3 ; (&) mixed with charcoal powder and soda lime (or with charcoal, dry Na 2 CO 3 and KCy) and (c) heated in a bulb tube, they yield a mirror and emit a garlic odour. Use 'oi gm. of Na 3 AsO 3 for each of the above tests. NOTE. Arsenical fumes are poisonous, therefore smell cautiously by wafting the fumes to the nose by the hand. . 3. Film test. Metallic, with SH 2 sol. : yellow. ARSENIOUS COMPOUNDS. WET TESTS. Diss. -i gm of Na 3 AsO 3 in 3 c.c. of aq. SH 2 (and HC1) : yellow ppt., As 2 S 3 , sol. in NH 4 SH, NaOH and (NH 4 ) 2 CO S , no ppt. in neutral or alkaline solutions. ANTIMONY 13 AgN0 3 : lemon yellow ppt. of Ag 3 AsO 3 , soluble in NH 4 OH and in acids. CuS0 4 : a ppt. of CuHAsO 3 (Scheele's green). ARSENIC COMPOUNDS. WET TESTS. Diss. '2 gm. Na 3 AsO 4 in 6 c.c. aq. SHe (and HC1) : warm and pass gas for some time : As. 2 S 3 and S. NOTE. Add H 2 SO 3 to reduce pentad As compounds to triad As com- pounds. AgN0 8 : red brown ppt. of Ag 3 AsO 4 . CuS0 4 : green ppt, CuHAsO 4 . MgS0 4 , NH 4 C1 and NH 4 OH ("magnesia mixture") : crystalline ppt. of MgNH 4 As0 4 . FeCl 3 : yellowish ppt. of FeAsO 4 . (NH 4 ) 2 Mo0 4 warm with slight excess of cone. HNO 3 : yellow ppt. of Am, arseno-molybdate. (See P 2 O 5 tests). MARSH'S TEST. All arsenious and arsenic compounds yield AsH 3 when added to a hydrogen generator, the H flame acquires a grey colour (from As 2 O 3 ) and deposits a metallic film of arsenic on cold porcelain, and a mirror of As within the exit tube, if that be heated. The zinc and acid must be free from As ; to prove this, ascertain whether a stain or mirror can be obtained from them before the As compound has been added. The mirror is sol. in NaClO. FLEITM ANN'S TEST. Warm the As compound in a test tube with Zn and NaOH ; the AsH 3 evolved blackens paper moistened with AgNO a sol. REINSCH'S TEST. Add a strip of bright Cu foil and a drop or two of HC1 to the sol., let it stand some time : grey deposit of As ; wash, dry and heat in bulb tube : crystals of As 2 O 3 . Antimony. Sb, 119-1 DRY TESTS. i. Blowpipe. Heat '02 gm. Sb 2 S 3 on char, with Na 2 CO 3 : white brittle metallic beads (sol. in aq. regia) and white incrustation. 2. Ignition tube. Antimony and Sb 2 S 3 when heated in a roasting tube (i.e., one open at both ends) give a white sublimate of Sb. 2 O 3 and Sb 2 O 4 . 3. Match test : white, brittle metallic beads of Sb. 4. Film test. Velvet black ; orange with SH 2 sol. ANTIMONIOUS COMPOUNDS. WET TESTS. Diss. o'i gm. of Sb 2 O s in 5 c.c. HC1 : SbCl 3 . SH 2 (and HC1) : orange ppt. of antimonious sulphide Sb. 2 S 3 , sol. in NaOH and in NH 4 SH, and in boiling HC1, insoluble in (NH 4 ) 2 CO 3 . (See As). NH 4 OH : white ppt., Sb 2 O 3 , insol. in excess. NaOH : white ppt., Sb 2 O 3 , sol. in excess to NaSbO 2 (Na metantimonite). Boil with bright copper foil and dil. HC1 : deposit of metallic Sb ; scrape off TIN and diss. in HC1 and dilute : white ppt. of SbOCl ; next pass SH 2 , the white ppt. turns to orange : Sb 2 S 3 . ANTIMONIC COMPOUNDS Dissolve o'i gm. of K. antimonate, K 3 SbO 4 in 5 c.c. aq. HC1 : ppt. sol. in excess of hot HC1. SH 2 : orange ppt. of Sb 2 S 5 , Sb 2 S 3 and S. Soluble in alkaline sulphides and hydroxides, with formation of antimonates and thio-antimonates. AgN0 3 : white ppt. of Ag 3 SbO 4 ; (antimonious salts free from chlorine : a black ppt. of Ag 2 O and Ag ; distinction between antimonic and antimonious salts). Antimonic salts in presence of HC1 also set free iodine from KI ; anti- monious salts do not. Tin. Sn, 118-1. DRY TESTS i. Blowpipe. Mix '02 gm. SnO 2 withNa 2 CO 3 and KCy and heat on char, in the reducing flame : white malleable beads, which do not mark paper, sol. in HNO 3 ; the HNO 3 sol. leaves a yellowish residue of metastannic acid Sn 5 O 5 (OH)i on evaporation to dryness ; metastannic acid is insol. in acids and in NaOH, but sol. after fusion with NaOH. 2. Match test : beads of metallic tin. 3. Film test. Black, with SH 2 aq. : yellow. STANNIC SALTS, e.g., SnCL,. WET TESTS. Diss. "2 gm SnCl in 6 c.c. aq. STANNOUS SALTS, e.g., SnCl 2 . WET TESTS. Boil *2gm. tin with 5 c.c. HC1, dilute to 10 c.c. HC1 : no ppt. SH 2 : dark brown SnS, sol. in NaOH (yields Na stannite and thiostannite) '; also .sol. in yellow NH 4 SH, and in cone. hot HC1. NH 4 OH : white ppt. of hydrated stan- nous oxide, Sn(OH) 2 . NaOH : white ppt. of Sn(OH) 2 , sol. in excess to Na 2 SnO 2 , Na stannite. HgCl 2 : white ppt. of HgCl ; boiled with excess of SnCl 2 : Hg as a grey ppt. AuCls : ppt. of pur pie of Cassius. : no ppt. : yellow SnS 2 , sol. in NaOH. (yields Na stannate and thio- stannate) ; also sol. in NH 4 HS white ppt. of H 2 SnO 3 si. sol. in excess and in tartaric acid. white ppt. of stannic acid, H 2 SnO sol. in excess, or of meta- stannic acid Sn 5 O 5 (OH)i , diffi- culty sol. in NaOH and in acids. no change. no change. IRON AND ALUMINIUM 15 GROUP IIlA. IRON, ALUMINIUM AND CHROMIUM. Iron. Fe, 55-6. DRY TESTS. i. Blowpipe. Heat '02 gm. of FeSO 4 on char, with NaoCOs, : black magnetic particles. Crush and wash in agate mortar ; pick out the magnetic particles with a magnetised penknife blade. Place on filter paper, add HC1 : yellow stain, add K*FeCy 6 : Prussian blue. 2. Match test : Same as on char. 3. Borax bead : practically insol. in excess and in NH 4 C1. NaOH : gelatinous A1(OH) 3 , sol. in excess to Na 3 AlO 3 , and not reprecip- itated on boiling ; reprecipitated by adding HC1 and NH 4 OH and boiling. NH 4 SH : white gelatinous A1(OH) 3 and SH 2 evolved. (NH 4 ) 2 C0 3 : white gelatinous A1(OH) S and CO 2 evolved. (NH 4 ) 3 P0 4 : white A1PO 4 , sol. in NaOH, KOH and sparingly in NH 4 OH, but insol. in NH 4 C1. Chromium. Cr, 51-7. DRY TESTS. Blowpipe, (a) Borax bead : emerald green in both flames, (b) Fused on Pt foil with Na 2 CO 3 and KNO 3 : yellow K and Na chromates. Diss. in acetic acid, add Pb acetate : yellow ppt. of Pb chromate. WET TESTS. Diss. "2 gm chrome alum (KCr2SO 4 .i2H 2 O) in 5 c.c. aq. NH 4 OH : green Cr(OH) 3 , insol. in excess on boiling. NaOH : green Cr(OH) 3 , sol. in excess to a green or violet colour, but re- precipitated on boiling. NH 4 SH : green ppt. of Cr(OH) 3 and SH 2 evolved, insol. in excess. (NHOaCOs : green ppt. of Cr(OH) 8 . Cl aq. or Br aq. in the cold oxidizes Cr salts to chromates. Cr forms both basic and acid salts. BASIC. ACID. CrO : chromous salts. Chromates contain CrO 3 (yellow). Cr 2 O 3 : chromic salts, mostly green. Bichromates contain 2CrO :j (red). If the Cr be present as an acid radicle (CrO 3 ) it must be reduced to the basic condition by boiling with cone. HC1 or with H 2 SO 3 before applying the above wet tests. Chromic Acid. H 2 Cr0 4 DRY TESTS. The same as for basic Cr. WET TESTS. Diss. o'i gm. of K 2 Cr 2 O 7 in 5 c.c. aq. and divide into 5 parts. HC1 : deep red colour, becomes green (CrCl 3 ) on boiling with alcohol (or SO 2 ) or on passing SH 2 through it. BaCl 2 : yellow, BaCrO 4 , sol. in acids. AgN0 3 : dark red Ag 2 CrO 4 . Pb2C 2 H 3 2 : yellow PbCrO 4 . H 2 2 (in ether) and one drop of dil. HC1, shake : deep blue solution. (Due to the unstable Cr 2 O-.) ZINC, MANGANESE AND NICKEL 17 GROUP IV. ZINC, MANGANESE, NICKEL AND COBALT. Zinc. Zn, 64-9. DRY TESTS i. Blowpipe. Heated on char, in inner flame with NaKCO 3 , Zn salts yield a yellow incrustation of ZnO,* white when cold ; moisten with Co2NO 3 and again heat before blowpipe : green residue. 2. Film test. Black, becomes white with SH 2 sol. WET TESTS. Diss. o'l gm. ZnSO 4 in 5 c.c. aq. NH 4 OH : white ppt, of Zn(OH),, in absence of NH 4 salts. KOH or NaOH : white ppt. Zn(OH) 2 , which is sol. in an excess of re- agent ; add NH 4 SH : white ppt. of ZnS. NH 4 SH : white ppt. of ZnS insol. in excess, NH 4 OH and NH 4 C1 facilitate its precipitation from dil. sols. Sol. in HC1, HNO 3 , and H 2 SO 4 , but insol. in acetic acid. (See Mn). (NH 4 ) 2 C0 3 : white basic Zn carbonate, ZnCO 3 ,3Zn(OH) 3 , sol. in excess. KCy : white ppt. of Zn(Cy) 2 , sol. in excess, from which it is precipitated by Na- 2 S as ZnS, but not by NH 4 SH. Manganese. Mn, 54-6. DRY TESTS Blowpipe. (a) Borax bead : an amethyst colour in the oxidising and a colourless bead in the reducing flame. (&) Fuse '01 gm. MnO 2 with a little Na. 2 CO 8 and KNOs on Pt foil or wire : green-coloured mass of K and Na manganates ; diss. this in a little very dilute H 2 SO 4 : red sol. of Na and K permanganates. WET TESTS. Diss. o'i gm. MnSO 4 in 5 c.c. aq. NH 4 OH : white ppt., Mn(OH),, sol. in NH 4 C1. NaOH : white ppt. of Mn(OH) 2 , insol. in excess ; rapidly oxidizes and turns to brown Mn 2 O 3 ,H 2 O. NH 4 SH : pinkish ppt. of MnS ; the fresh ppt. is sol. in acetic acid. Na-jCOa : white MnCO 3 , sol. in NH 4 C1, oxidizes and becomes brown. KCy : white Mn(Cy) 2 , soluble in excess. Nickel. Ni, 58-3. DRY TESTS. Blowpipe, (a) Borax bead : grey in inner, reddish in outer flame ; a little KNO 3 renders the bead purple, (d) On char, with Na 2 CO 3 , or on match : black, slightly magnetic particles. Use magnetised penknife blade. * Zinc is volatile, but ZnO is not. 1 8 NICKEL AND COBALT WET TESTS. Diss. o'i gm. of NiSO 4 in 7 c.c. of aq. NH 4 OH : light green ppt.> Ni(OH) 2 , sol. in excess to a blue solution. NaOH : light green Ni(OH) 2 insol. in excess, but sol. in NH 4 salts, and in acids. NH.SH : black ppt., NiS, insol. in acetic and hydrochloric acids, slightly sol. in NH 4 SH, and in NH 4 OH. The sol. is brown. NaCIO sol. , boil : black Ni(OH) 3 . (NH 4 ) 2 C0 3 : green ppt., basic NiCO 3 , sol. in excess. KCy : greenish ppt, Ni(Cy) 2 , sol. in excess to a brown sol. of 2KCy, NiCy 2 ; reprecipitated by acids (see Co); to the sol. in KCy add Br aq. until of a permanent brown colour ; warm : black ppt. of Ni(OH) 3 . K 4 FeCy 6 : greenish ppt. , Ni a FeCy c . Cobalt. Co, 58*56. DRY TESTS. Blowpipe, (a) Borax bead : blue in ,ooth reducing and oxidizing areas, (b) On char, with Na 2 CO 3 , or with match test : black mag- netic particles. Use magnetised penknife blade. WET TESTS. Diss. -2 gm. of Co2NO 3 in 7 c.c. aq. NH 4 OH, in absence of NH 4 C1, : blue ppt. of basic salt, sol. in excess to a brown sol., which momentarily becomes purple on boiling. NaOH : a blue ppt. of basic salt, Co(OH) 2 ,Co2NO 3 , insol. in excess, becomes green on standing, and pink, (Co(OH) 2 ) or brown on warming, dissolves in (NH 4 );CO 3 (after washing) to a deep purple sol. NH 4 SH : a black ppt. of CoS difficultly sol. in dil. HC1 or H 2 SO 4 , but readily sol. in warm aqua regia. (NH 4 )oC0 3 : rose coloured ppt., sol. in excess. KCy : brown ppt. of CoCy 2 , sol. in excess to 2KCy,CoCy 2 ; when boiled with a drop of HC1 to set free HCy, K 3 CoCy c (pot. cobalti-cyanide) is formed, from which Co(OH) 3 is not precipitated by HC1 nor by NaCIO. (Compare NiCy 2 ). To separate Co and Ni by this reaction, add KCy until the ppt. only just redissolves, then add two or three drops of acetic acid, boil for three minutes ; cool, filter off any ppt. which forms, make alkaline with NaOH, add Br aq. until the sol. remains yellow to brown in colour, warm : black ppt. of Ni(OH) 3 . Filter, evaporate filtrate and test for Co by borax bead. <* K 4 FeCy 6 : a dark green ppt. of Co 2 FeCy e . KN0 2 and acetic acid to a neutral sol. : bright yellow crystalline ppt. of K 8 Co(NO 2 ) 3 (pot. cobaltinitrite). This reaction also serves for the separation of Co from Ni ; add two or three c.c. of alcohol and shake the mixture, let stand for fifteen or twenty minutes, filter off the K s Co(NO 2 ) 3 , and add NaOH to the filtrate : Ni(OH) s . BARIUM, STRONTIUM AND CALCIUM 19 GROUP V. BARIUM, STRONTIUM AND CALCIUM. Barium. Ba, 136-4. DRY TKST. Ba salts colour the bunsen flame pale green, especially when moistened with HC1. WKT TKSTS. Diss. 0*1 gm Bad, in 5 c.c aq. (NHO-jCOs : white ppt. of BaCCX, sol. in diL.HCl, slightly soluble in NH 4 C1. CaS0 4 or other sulphates or dil. H 2 SO 4 : an immediate ppt. of BaSO 4 even in dil. sols. Insol. in dil. acids and alkalis. (NH 4 ) 2 C 2 4 : white granular ppt. of BaC 2 O 4 . K 2 Cr0 4 : pale yellow ppt. of BaCrO 4 from even dil. sols. ; sol. in HC1 and HNO 3 ; insol. in acetic acid ; SrCrO 4 and CaCrO 4 are sol. H 2 SiF, ; gives a white crystalline ppt. of BaSiF 6 , hastened by the addition of alcohol ; Ca and Sr salts are not precipitated by H 2 SiF 6 . Strontium. Sr, 86-94. DRY TEST. Sr salts colour the flame red. WET TESTS. Diss. o' i gin. of SrCLj in 5 c.c. aq. (NHOaCOs : white ppt. of SrCO 3 . H 2 S0 4 (dil.) or a sol. sulphate throws down white SrSO 4 . If CaSO 4 is used or the sol. be dilute the ppt. will take some time to form ; hastened by boiling with (NH 4 ) 2 SO 4 , in which CaSO 4 is soluble. Na 2 HP0 4 ; a white ppt. of Sr 3 2PO 4 . (NH 4 ),C,0 4 : white ppt. of SrC,O 4 . K 2 Cr0 4 : pale yellow ppt. of SrCrO 4 , sol. in acetic and other acids. Calcium. Ca, 39-8. DRY TEST. Ca salts colour the flame orange red. WET TESTS. Diss. *i gm. CaCl 2 in 5 c.c. aq. (NH 4 ) 2 CO ; <, in the presence of NH 4 C1, gives a white ppt. of CaCO 3 . Ignite ppt. on Pt wire : CaO ; place this residue on moist red litmus paper : blue. H 2 S0 4 , or a sulphate (except CaSO 4 ) : white ppt. of CaSO 4 from strong sols., or from weak ones on adding alcohol. Na 2 HP0 4 and NH 4 OH : bulky white ppt. of Ca 3 P 2 O M , sol. in HC1 and HNO 8 . (NH 4 ) 2 C 2 4 : white ppt. of Ca oxalate (CaC 2 O 4 ) insol. in acetic acid ; sol. in HC1. K 2 CrOi, no ppt. unless the solution is very strong. 20 MAGNESIUM, POTASSIUM AND SODIUM GROUP VI. MAGNESIUM, POTASSIUM, SODIUM, AMMONIUM AND LITHIUM. Magnesium. Mgy 24-18. DRY TEST. Blowpipe. Mg salts on char, or Pt wire : a white luminous residue, moisten this with Co2NO 3 and heat strongly : pink residue. WET TESTS. Diss 'i gm. MgSO 4 in 4 c.c. aq. NH 4 OH : white gelatinous ppt. of Mg(OH) 2 i.e., in the absence of NH 4 C1, otherwise soluble double salts are formed. ?KOH, NaOH, Ca(OH) 2 , and Ba(OH> 2 throw down Mg(OH), in the absence of NH 4 salts. Mg(OH) 2 is only slightly soluble in aq. (NH 4 ) 2 C0 3 : white crystalline ppt. of Mg(NH 4 ),2CO, (after some time) if NH 4 salts are absent. Na 2 HP0 4 in the presence of NH 4 OH and NH 4 C1 : crystalline ppt. of Mg(NH 4 )PO 4 , especially when stirred or shaken. Dilute solutions should be allowed to stand some time. Potassium. K, 38-86. DRY TESTS. i. K salts colour the bunsen flame lilac to violet; if the flame be yellow from the presence of sodium examine it through blue glass or an indigo prism, so as to cut out the yellow rays ; if lithium be present, view 7 the flame through four or five thicknesses of blue glass. 2. Confirm with spectroscope. 3. Blowpipe. On charcoal, K salts fuse and sink into the charcoal, and colour the flame greyish or pale lilac. WET TESTS. Diss. '2 gm. KC1 in 3 c.c. aq. Chloroplatinie Acid, ''Platinum chloride," (H 2 PtCl fi ) : a yellow crystal- line ppt. of K 2 PtCl 6 , insol. in acids and in alcohol ; sol. in KOH. Tartarie Acid, H 2 C 4 H 4 O ti , or sodium hydrogen tartrate NaHC 4 H 4 O 6 : white crystalline ppt. of KHC 4 H 4 O 6 from neutral solutions ; its formation is hastened by stirring and shaking, and by the addition of alcohol. H 2 SiF 6 : a gelatinous ppt. of K 2 SiF 6 , sol. in aq. (i in about 800); insoluble in alcohol. Sodium. Na, 22-88. DRY TEST. Na salts colour the bunsen flame yellow ; seen through blue glass or an indigo prism it appears colourless. WET TESTS. There are no satisfactory tests for sodium in solution. AMMONIUM, LITHIUM AND TUNGSTEN 21 Ammonium. (NH 4 ) DRY TESTS. i. Ignition tube. Most ammonium salts when heated in a dry tube yield a white sublimate, either with or without the evolution of NH 3 , which is recognised by its smell and the bluing of red litmus. 2. Ammonium salts warmed with Ca(OH). 2 or NaOH sol; : NH 8 gas. WET TESTS. Diss. '2 gm. NH 4 C1 in 3 c.c. of aq. Chloroplatinie aeid, "Platinum chloride," H 2 PtCl 6 : yellow ppt. of (NH 4 ) 3 PtCl 6 similar to that from K salts ; ignite the (NH 4 ) 2 PtCl 6 on porce- lain : residue of grey spongy platinum. Tartarie aeid, H 2 C*H 4 O 6 : white" crystalline ppt. of (NH 4 )HC 4 H 4 O (i ; ignite : carbon free from alkaline reaction. Nessler's test for minute traces of NH 3 : a yellow or brown colouration (due to NHg. 2 I,H a O). Test for NH 3 in the distilled aq. used. Lithium. Li, 6-98. DRY TESTS. Li salts colour the bunsen flame crimson ; Na changes it to orange, but the Li is recognisable if the flame be viewed through the thinner parts of the indigo prism. A silicate must be fused with CaSO 4 , and.LisPC^ moistened with HC1 to obtain the flame colouration. Li is easily recog- nised in the spectroscope by the single red and orange bands. WET TESTS. Diss. o.i gm. of LiCl in 3 c.c. of aq. NaJHP0 4 and NaOH, boil : a white crystalline ppt. of 2Li 8 PO 4 ,H 2 O. If traces only of Li are present, add Na< 2 HPO 4 and NaOH, and evaporate to dryness and wash the residue with dil. NH 3 . Na 2 C08, (K. 2 CO 3 or (NH 4 ). 2 CO 3 ) with an equal vol. of alcohol : ppt. of Li^COa. Lithium in waters. Concentrate, add Ba(OH). 2 and cool ; then add (NH^COs and filter ; to the filtrate add Na 3 HPO 4 , take up with a small quantity of aq., residue : Li i phosphate. Confirm by the flame test. Li differs from K and NH 4 by not being precipitated by H 2 PtCl 6 or by H 2 C 4 H 4 O (i . LiCl can be separated from KC1 and NaCl by a mixture of absolute alcohol and ether, in which it is insoluble. RARER METALS OF GROUP I. TUNGSTEN, THALLIUM AND NIOBIUM. Tungsten or Wolfram. W, 182-6. DRY TESTS. Blowpipe. (a) Heat '02 gm. Na. 2 WO 4 on char, with Na. 2 CO 3 and KCN : black impure tungsten. () Mieroeosmie salt, in outer flame : colourless or yellow bead ; in inner flame : blue bead ; re-fused with a little 'powdered FeSO 4 : blood red when cold. 22 THALLIUM WET TESTS. Diss. o'i gm. Na. 2 WO 4 in 5 c.c. aq. HC1, HN0 3 or H 2 S0 4 : white ppt. of H. 2 WOi ; yellow on boiling, sol. in NH 4 OH ; add fragment of zinc : blue colour. SH 2 : no ppt., but H 2 WO 4 is reduced to the blue W. 2 O,> HC1 and Zn : the deep blue W. 2 O 5 , turning to brown WO 2 . SnCla in neutral sol. : yellow ppt. of WO. 2 (?) add HC1 and warm : blue. NEUSH : no ppt. until HC1 is added, the sol. turns blue and a brown ppt. of WS 3 forms ; readily sol. in NH 4 SH. Thallium. Tl, 202-6. Thallium is partly thrown down as chloride in Group I with Pb, etc., also in Group II with As, and partly as sulphide in Group IV. Examine As. 2 S a for Tl, as Tl may come down with it. DRY TKSTS. Flame test : strong green colour, and one bright green band in the spectrum. THAUJOUS COMPOUNDS. WET TESTS. Diss. *i gm, T1. 2 SO 4 in 7 c.c. aq. HC1 : white ppt. of T1C1, sol. in aq. regia ; is not blackened by light Slightly sol., hence not formed in dil. solutions. SH 2 : black T1 2 S, only partly precipitated, except in acetic acid sol. KI : yellow ppt. Til, nearly insol. in aq., more sol. in KI. H 2 PtCl 6 : orange ppt., Tl. 2 PtCl 6 slightly sol. in aq. NH 4 SH : black ppt., clots on boiling, insol. in NH 4 OH, in alkaline sul- phides and in KCN ; oxidised by the air to T1. 2 SO 4 , which is readily sol. in mineral acids. K 2 Cr0 4 : yellow Tl. 2 CrO 4 insol. in cold HNO 3 . Zn : metallic Tl. THALLIC COMPOUNDS. WET TESTS. Diss. 'oi gm. T1C1 3 in 5 c.c. aq. HC1 : no ppt. SH 2 : reduces thallic to thallious salts, with separation of S. KI : ppt. of yellow Til, and free I. K 2 Cr0 4 : no ppt. H 2 C 2 4 : white ppt. of Tl oxalate. To detect Tl in pyrites, etc., and in the residue left by Zn when dis- solved in HC1, diss. in aq. regia, add H. 2 SO 4 and boil off the HNO 3 , add Na 2 SO 3 to reduce to ferrous and thallious salts, then add KI, when yellow Til is precipitated. NIOBIUM, OSMIUM AND PALLADIUM 23 Niobium or Columbium. Nb, 93-3. DRY TEST. Blowpipe. Microcosmic salt : colourless bead in the OF while hot, in the RF : violet, blue, or brown ; add a little FeSO 4 : red colour. WET TESTS. Diss. *oi gm. KNbO 3 in 5 c.c. aq. H 2 S0 4 and other mineral acids : ppt. of Nb(OH) a . NH 4 OH or NH 4 SH : ppt. of Nb(OH) 3 , sol. in HF. K 4 FeCy e and two drops of HC1 : red ppt. K 3 FeCyc, : yellow ppt. Zn and HC1 : blue ppt. which changes to brown. RARER METALS OF GROUP HA. OSMIUM AND PALLADIUM. Osmium. Os, 189-6. DRY REACTION. Volatilizes at a very high temperature as OsO 4 without fusion. WET TESTS. Diss. '01 gm. OsO 4 in 5 c.c. aq. SH 2 (in acid solutions) : brown black ppt. of OsS. Alkalis and their carbonates : reddish brown ppt. of Os(OH) 4 . Tannie acid (or alcohol) and HC1 reduce it to the blue osmious chloride, OsCL. Indigo solution is bleached. Na 2 S03 : deep violet colour, and a ppt. of blue osmious sulphite gradually forms. Palladium. Pd, ios-7. DRY TEST. Heat a small particle of PdCL 2 on porcelain : a residue of Pel. All Pd salts yields Pd on ignition. PALLADIOUS SALTS. WET TESTS. Diss. -05 PdCl 2 in 10 c.c. aq. and two drops HC1. SH-2 or NH 4 SH : black ppt. of PdS in neut. alk. and acid solutions, insol. in NH 4 SH, but sol. in hot HC1 or aq. regia. NH 4 OH : pink ppt. of PdCl. 2 .2NH 3 , sol. in excess. HgCy 2 : yellowish gelatinous PdCy 2 , slightly sol. in HC1, readily in NH 4 OH ; heated : spongy Pd. (Characteristic.) KI : black ppt. of PdI 2 , sol. in excess of KI. (Characteristic.) KC1 : brown red 2KCl,PdCl 2 , on standing. NH 4 C1 : no ppt. (Difference from Pt). Iodine (tincture) forms a black stain on Pd, but not on Pt. SnCl 2 : brown-black ppt., sol. in HC1 to a green sol. 24 GOLD KOH : light brown basic salt, sol. in excess. Na>S 2 3 (a few drops in NH 4 OH) : pale yellow solution ; on boiling be- comes black. PALLADIC SALTS. WET TESTS. Diss. i mgm. of PdCl 4 in 2 c.c. aq. KOH : brown ppt. of Pd(OH) 4 . Boil : black PdO>. KC1: bright red crystalline ppt. of 2KCl,PdCl 4 or K. 2 PdCl (; . THE RARER METALS OP GROUP HB. GOLD, PLATINUM, IRIDIUM, MOLYBDENUM, SELENIUM AND TELLURIUM. Gold. Au, 195-7. DRY TEST. Blowpipe. Heated on char, or on match, all gold com- pounds are decomposed and the metal is left ; if the charcoal or match end be ground in an agate mortar and the charcoal be very carefully washed away, so as not to float off gold with it, very minute traces of gold can be detected in this way. The spangles of gold are insol. in H 2 SO 4 , in HC1 free from Cl, and in HNO 3 free from N. oxides ; sol. in aq. regia. WET TESTS. Diss. -01 gm. NaAuCl 4 ,2H 2 O (photographers' " gold chloride ") in 10 c.c. aq. SHo in cold sols. : black Au. 2 S 3 (auric sulphide). SH2 in hot sols. : brown Au 2 S (aurous sulphide) mixed with free gold, if long boiled the whole is reduced to metallic gold. Both Au>S and Au. 2 S 3 are sol. in aq. regia, in yellow NH 4 SH, and in yellow Na 2 S. FeS0 4 : ppt. of metallic gold. S0 2 : ppt. of metallic gold. H 2 C 2 4 on warming : ppt. of metallic gold. NH 4 OH : pale orange ppt. of fulminating gold (Au, N, and NH 3 ) sol. in excess. This ppt. explodes with great violence, especially when dried and heated. SnCl 2 and three drops of FeCl 3 : purple of Cassius. P dissolved in ether, : red or purple colour, even in exceedingly dil. AuCl 3 , say one part of Au in 1,000,000 of aq. Zn and most metals precipitate gold from its solutions. Iodine tincture readily dissolves out traces of gold from quartz, etc. Agitate five or ten grammes of the finely-powdered mineral with a tincture of iodine, let stand, dip a strip of white filter paper into the clear liquid, dry and burn ; if gold be present the ash will be purple or brown, if much gold be present, on rubbing the ash in a mortar (agate) it will show the colour of PLATINUM, IRIDIUM AND MOLYBDENUM 25 burnished gold. Merely grinding ores in an agate mortar and washing carefully is usually quite sufficient to detect even traces of gold. But where it is practicable the ore may be first treated with HC1 free from Cl, or HNO 3 free from N. oxides, to remove other metals ; remove silica by HF. Platinum. Pt, 193-3. DRY TEST. Heat 0*1 gm. or less of PtCl 4 on char, or match, crush in agate mortar and wash away the char, powder : grey metallic Pt. Insol. in H 2 SO 4 , in HC1 and in HNO 3 , but sol. in aq. regia. WET TESTS. Dissolve '05 gm. H 2 PtCl 6 in 7 c.c. aq. SH 2 : dark brown ppt. of PtS 2 , favoured by warming ; insol. in HC1 and HNO 8 , but sol. in aq. regia and in yellow NH 4 SH. NH 4 SH : PtS 2 , as above. NH 4 C1 and 2 c.c. alcohol : yellow crystalline ppt. of (NH 4 ) 2 PtCl 6 . KC1 and 2 c.c. alcohol : yellow crystalline ppt. of K 2 PtCl 6 . Zn : ppt. of metallic Pt. SnCl 2 : brown-red colour from formation of PtCl 2 . To separate Au and Pt from solution, reduce the Au by H 2 C 2 O 4 , filter off, and then evaporate with NH 4 C1 to obtain the Pt as (NH 4 ) 2 PtCl 6 . Iridium. Ir, 191*5. DRY TESTS. i. Fused with KHSO 4 it is oxidized, but not dissolved. (Distinction from Rh.) 2. Heat a minute particle of any Ir salt on char, or porcelain : finely-divided Ir. WET TESTS. Diss. '02 gm. IrCl 3 in 5 c.c. aq. SH 2 : the colour is discharged, S set free, and a brown ppt. of iridic sulphide Ir a S s forms. NH 4 SH : same as SH 2 ; sol. in excess. KOH in excess : green colour, and a dark [brown ppt. of K 2 IrCl 6 ; warm the solution : red colour changing to blue (distinction from Pt) ; evaporate to dryness with aq. : blue residue of IrO 2 . KC1 : dark brown ppt. of K 2 IrCl 6 . NH 4 C1, from strong sols. : dark red crystalline ppt. of (NH 4 ) 2 IrCl 6 Molybdenum. Mo, 95-3 DRY TESTS. i. In bunsen flame : yellowish green colour. 2. Blowpipe. On char., or match, in inner flame : grey powder of Mo ; in outer flame : yellow crystalline incrustation, white on cooling. 3. Borax bead. In outer flame, yellow ; in inner, dark brown bead. 26 SELENIUM 4. Mierocosmic salt. Green bead in inner and outer flames. WET TESTS. Diss. OT gm. (NH 4 ) 2 MoO 4 in 10 c.c. aq. HC1 (or HN0 3 or H 2 S0 4 ) on boiling throws down white MoO 3 , sol. in excess of acid ; evaporate to dryness with H 2 SO 4 : blue colour. SH-2 (in acid sol.) : a blue colour and then a brown ppt. of MoS 3 ; warm and pass SH 2 for some time for complete precipitation. Sol. in alkalis and alk. sulphides. NH 4 SH : same as SH 2 ; sol. in excess. SnCl 2 , or Zn and HC1 : brown, green or blue colour according to the degree of concentration. KCNS, or zinc and HC1 : crimson colour, which can be taken up by ether. Na 2 HP04 (OP Na 3 As0 4 ) and HN0 8 on warming : yellow ppt., sol. in excess of alkalis. In minerals, e.g., Molybdenite (MoS 2 ), or Wulfenite (PbMoO 4 ), first heat with dil. HC1 to dissolve out Fe and Zn, extract residue with strong HC1 and evaporate to dryness. Digest with NH 4 OH, filter and concentrate, when crystals of (NH 4 ). 2 MoO 4 separate, to which the usual tests can be applied. Selenium. Se, is-s. DRY TESTS i. Blowpipe, (a) On char, in inner flame : odour of decaying horse-radish. Se burns with a bluish flame to SeO 2 . (b) On char, with Na 2 CO 3 , in inner flame or on match : fused mass of Na selenide, Na 2 Se ; this placed on a silver coin and moistened yields a black stain, and with HC1 the characteristic odour of SeH 2 . 2. Heated in a roasting tube, selenides evolve a peculiar odour of decaying horse-radish and yield a red sublimate of Se. SELENITES. WET TESTS. Diss. 'i gm. of Na selenite (Na 2 SeO 3 ) in 7 c.c. aq. SH 2 in e ld acid sol. : yellow ppt. ; in hot sol. : an orange ppt. (SeS 2 ?) which soon decomposes into free S and Se, sol. in NH 4 SH. BaCl 2 , in neutral sols. : white ppt. of BaSeO 3 , sol. in HC1 and in HNO 3 . SnCla OP H 2 S0 3 (and 2 drops of HC1) : red ppt. of Se, which becomes grey on heating. Cu and HC1, warm : ppt. of black Se, which after standing becomes red. Mg OP Zn in slightly acid sols. : red flakes of Se. Diss. out any excess of Mg or Zn with HC1 ; the Se is left in the form of the metallic fragments of Mg or Zn. TELLURIUM 27 KI : scarlet ppt. of SeI 4 . This on heating quickly sublimes, the sub- limate is hardly distinguishable from that of Se itself. Selenates also give the above reactions after reduction to selenites by boiling with HC1. SELENATES. WET TESTS. Diss. *i gm. of K 2 SeO 4 in 3 c.c. aq. HC1 : no change ; boil, Cl is evolved and the selenate is reduced to selenite. SH 2 : no ppt. at first, i.e., until the selenate has been reduced to selenite by the SH 2 . BaCl 2 : a white ppt. of BaSeO 4 , insol. in cold but sol. in hot HC1, with evolution of Cl and reduction to Ba selenite. Tellurium. Te, 126. DRY TESTS. i. Blowpipe. On char. : thin white incrustation. 2. Tellurides, Tellurites and Tellurates when fused with Na 2 CO s on char, or on match in the inner flame : Na telluride ; this placed on a silver coin and moistened produces a black stain, and with HC1 it yields black Te, and TeH 2 which smells something like SH 2 . 3. For minerals (Tellurides) use KCy as well as Na 2 CO 3 . 4. Tellurides heated in a roasting tube : white fusible sublimate of TeO 2 . To extract from minerals, fuse '2 gm. with ten times the weight of KCy in a bent, hard-glass tube through which H is passed, K 2 Te is formed. Extract this with aq. : red solution ; on passing a current of air through this, scales of Te are precipitated; heat on char., a slight odour is emitted and white TeO 2 is deposited. TELLURITES. WET TESTS. Diss. '2 gm. of K 2 TeO 3 in 6 c.c. aq. or 'i gm. Te in 5 c.c. of strong HNO 3 , and nearly neutralize with NaOH. H 2 : ppt. of white H 2 TeO 3 (from acid sols.) HC1 : ppt. of white H 2 TeO 3 (from the HNO 8 sol.) SH 2 : ppt. of brovvn TeS 2 in acid sols., easily sol. in NH 4 SH. H 2 S0 3 , SnCl 2 , or Zn and HC1 : ppt. black Te ; insol. in KCy. TELLURATES. WET TEST. Diss. o'i gm. K 2 TeO 4 in 2 c.c. aq. HC1 : no change : boil, Cl is evolved and the tellurate is reduced to tellurite ; on dilution, H 2 TeO 3 comes down. 28 BERYLLIUM AND CERIUM THE RARER METALS OF GROUP III. are thrown down by NH 4 OH as hydroxides or acids : Beryllium hydroxide Be(OH) 2 Zirconium hydroxide Zr(OH) 4 Thorium Th(OH) 4 Scandium hydroxide Sc(OH) s Yttrium ,, Y(OH) 3 Titanium hydroxide H 2 TiO 3 Ytterbium ,, Yb(OH) 3 Tantalum ,, H 3 TaO 4 Cerium ,, Ce(OH) 3 Niobium ,, H 3 NbO 4 lanthanum , , I^a(OH) 3 The reactions for the salts of Scandium, Yttrium, and of some of the other rare metals are omitted on account of the difficulty of obtaining them in a pure condition. Beryllium (Glucinum.) Be, 9. DRY TEST. Blowpipe. On char, with Co 2 2NO 3 : a grey mass ; not distinctive. WET TESTS. Diss. o'i gm. BeSO 4 in 5 c.c. aq. NEUOH, (NaOH, KOH or NH 4 SH) throws down flocculent Be(OH) 2 , sol. in KOH, but reprecipitated by dilution and long boiling; not sol. in NH 4 OH, but the fresh ppt. is slowly dissolved by boiling with NH 4 C1. Alk. carbonates : white ppt. of basic carbonate, sol. in excess, repre- cipitated on dilution and long boiling, thus distinguished from Al. BaC0 3 ' white Be carbonate. To separate BeO from A1 2 3 . Diss. in HC1, pour slowly, with constant stirring, into a hot cone. sol. of (NH 4 ) 2 CO 3 : ppt. of A1(OH) 3 ; filter, neu- tralize with HC1, boil, add NH 4 OH : ppt. of Be(OH) 2 . Cerium. Ce. 139-0. DRY TESTS. i. Blowpipe. On charcoal : reddish brown CeO 2 . 2. Borax bead, outer flame : red when hot, colourless when cold ; inner flame : colourless ; but CeO 2 : yellow opaque bead. CEROUS SALTS. WET TESTS. Diss. -05 gm. CeCl 3 in 8 c.c. of aq. NH 4 OH : white ppt. of the basic salt ; tartaric acid prevents this, (dis- tinction from Y) ; insol. in excess, becomes yellow on exposure. NaOH : white gelatinous ppt. Ce(OH) 3 , somewhat soluble, gradually oxidizes and becomes yellow ; Cl water, NaCIO, etc., bring about the same change more quickly. LATHANUM, DIDYMIUM AND ZIRCONIUM 29 (NH 4 ) 2 S : Ce(OH) 3 , cerous hydroxide, insol. in excess. H 2 C 2 4 : curdy white ppt. of Ce. oxalate, insol. in excess (distinction from Zr), difficultly sol. in HC1 (Al and Be oxalates are soluble). Converted into CeO 2 on roasting. NaCIO, or Am. persulphate on boiling : yellow or red ppt. Na 2 C0 3 , KaCOs or (NH 4 ) 2 C0 3 : ppt. of Ce^CO,. BaC0 3 : complete precipitation on standing. KHS0 4 saturated sol. : crystalline ppt. of Ce 2 (SO 4 )3,3K 2 SO 4 (distinction from Be and Al) ; insol. in a saturated sol. of K 2 SO 4 (distinction from Y and Er). CERIC SALTS. The salts of CeO 2 are yellow and insoluble, or sparingly sol. in aq. Lanthanum. La, 137-9. DRY TEST. Blowpipe. I^Oa undergoes no change. WET TESTS. Diss. '01 gm. L,aCl 3 in 4 c.c. aq. NH 4 SH and NH 4 OH : ppt. of basic salts; milky on washing. NaOH : I/a hydroxide, L,a(OH) 8 , insol. in excess ; unchanged by oxidising reagents (distinction from Ce). (NH 4 ) 2 C0 3 : white ppt., insol. in excess (distinction from Ce). Didymium. (Neodymium 1*2-5 and Praseodymium 139-4.) DRY TEST. Blowpipe. Heated on char. Di salts leave a grey residue. WET TESTS. Diss. '01 gm. DiCl 3 in 5 c.c. aq. NH 4 OH and NH 4 SH : basic salt, insol. in NH 4 OH, but somewhat sol. in NH 4 C1. NaOH : pale rose-coloured gelatinous Di(OH) 3 , insol. in excess. Na 2 C0 3 : Di(CO 3 ) 3 , insol. in excess (distinction from Ce), but slightly sol. in NH 4 C1. BaCOs : Di(CO 3 ) 3 , slowly and incompletely. (NH 4 ) 2 C 2 4 : ppt., slowly sol. in cold HC1 ; readily on warming. Di sols, yield characteristic absorption bands in the spectroscope. Zirconium. Zr, 89*9. DRY TESTS. i. Blowpipe. ZrO 2 becomes strongly luminous; re-heat with Co2NO 3 : a dull violet colour. 2. Bopax bead, colourless ; somewhat opaque when cold. WET TESTS. Diss. .05 gm. Zr(SO 4 ) 2 in 10 c.c. aq. 30 THORIUM AND TlTANUM NH 4 OH : white flocculent ppt. of Zr(OH) 4 , insol. in excess and in NaOH. (Distinction from Al and Be). NH 4 SH : same as NH 4 OH. NaOH : same as NH 4 OH, but soluble in boiling NH 4 C1. (Distinction from Be) (NH 4 ) 2 C0 3 : white flocculent ppt. of basic carbonate, sol. in excess, repre- cipitated on boiling. (Distinction from Al.) BaC0 3 : no ppt. cold, partly precipitated when boiled. H 2 C 2 4 '. voluminous white- ppt. of Zr oxalate (distinction from Al and Be); sol. in excess of (NH 4 ) 2 C 2 O 4 (distinction from Th and Ce.) Na 2 S 2 08, boil : ppt. of ZrS 2 O 3 . (Distinction from Y, Er and Di.) K 2 S0 4 with Zr(S0 4 ) 2 : ppt. of the double sulphate of Zr and K, insol. in excess of K 2 SO 4 , sol. in HC1. (Distinction from Al and Be.) K 2 S0 4 is added to hot Zr(SO 4 ) 2 : the double sulphate is almost insol. in H 2 O and HC1. (Distinction from Th and Ce.) Thorium. Th, 230-8. DRY TESTS. i. Blowpipe. ThO 2 is infusible; no characteristic colour with Co2NO 3 . 2. Borax bead : colourless. WET TESTS. Diss. '2. gm. Th2SO 4 in 8 c.c. aq. NH 4 OH or NaOH : white gelatinous Th(OH) 4 , insol. in excess. NH 4 SH : same as NH 4 OH or NaOH. (NH 4 ) 2 C0 3 , Na 2 C0 3 OP K 2 C0 3 : ppt. of white basic carbonate, readily sol. in excess, but reprecipitated from (NH 4 )>CO 3 at 50. BaC0 3 : Th2CO 3 without warming. H 2 C 2 4 : white Th2C 2 O 4 (distinction from Al and Be), not sol. in excess nor in dil. mineral acids ; sol. in NH 4 C 2 H 3 O 2 acidulated with HC 2 H 3 O 2 (dis- tinction from Y and Ce) ; sol. in hot Am. oxalate (distinction from Ce). HF : gelatinous ThF 4 , which gradually becomes granular ; insol. in H 2 O and HF (distinction from Al, Be, Zr, Zn and TiO 2 ). Na 2 S 2 3 : from neutral or acid sols, partially precipitates ZrS 2 O 8 , mixed with free S. Titanum. Ti, 47-7. DRY TESTS. i. Blowpipe. On char. : no change. 2. Miepoeosmie salt bead i n outer flame : yellow while hot, eoloupless when cold ; in inner flame : yellow while hot, violet when cold. Add a particle of Sn or Zn to the bead and re-fuse in the reducing flame : brighter violet, or add a particle of FeSO 4 : a blood-red bead in the inner flame. TANTALUM AND URANUM 31 WET TESTS. (a) Boil O'l gm. Ti0 2 in 3 c.c. cone. H,SO 4 or HC1, dilute with 5 c.c. aq. and filter, (b) To dissolve the Ti0 2 completely, fuse T gm. with KHSO 4 on a porcelain lid ; dissolve the yellow mass in cold water, then add a few drops of HC1 to make a clear solution. The alkalis, their sulphides and carbonates, and BaC0 3 give white floccu- lent ppts. of orthotitanic acid, H 2 TiO 3 , insol. in excess ; if precipitated and washed in the cold it is sol. in HC1 and H 2 SO 4 ; hot aq. converts it into the insoluble metatitanic acid. Zn or Sn in acid sols. : blue ; if dilute : a rose colour. The TiO 2 is re- duced to blue or purple Ti 2 O 3 , this gradually oxidizes to TiO 2 and loses colour. Na 2 S 2 3 on boiling completely precipitates white TiO 2 . K 4 FeCy 6 : dark brown ppt. (the presence of Fe interferes.) Tannie acid : brown ppt., changing to orange. Tantalum. Ta, 181.6. DRY TESTS. i. Blowpipe. Ta 2 O 5 becomes yellow when strongly ignited, and insol. in HC1 and H 2 SO 4 . 2. Mieroeosmie salt bead : colourless in both flames. WET TESTS. Diss. '02 gm. KTaO 3 in 5 c.c. aq. HC1 : ppt. of Ta. 2 O 5 , sol. in excess of HC1. NH 4 OH or NH 4 SH : a ppt. (HTaO 8 or NH 4 TaO 3 ,HTaO 3 ? ). K 4 FeCy<3 : white ppt. ; add NH 4 OH : brown. KsFeCyc : yellow ppt. Zn and HC1 : no change or a faint blue colour. (Distinction from Nb 2 O 5 ) THE RARER METALS OF GROUP IV. Thrown down by NH 4 SH as : Uranyl sulphide (UO 3 )S Indium sulphide InS Thallious sulphide T1 2 S (also in Group I). Vanadium compounds are converted by NH 4 SH into soluble ammonium thio-vanadate from which HC1 precipitates V 2 S 3 . Uranium. U, 236-7. DRY TESTS. Blowpipe. Borax and rnicrocosmic salt beads in outer flame : yellow ; in inner flame : green bead. Not reduced on char, with Na 2 CO 3 . 32 INDIUM In minerals. Roast a small quantity of the mineral and diss. in HNO 3 , evaporate to dryness ; take up with water, filter (or add an excess of Na 2 CO 3 and boil, filter off the carbonates of Fe, Ca,.etc.) and add KOH, when the yellow U(OH) 4 is thrown down. UR ANGUS SALTS. Uranous salts are green or greenish. WET TESTS. Diss. 0*1 gm. U(SO 4 ) 2 in 5 c.c. aq., or reduce *i gm. uranic nitrate by Zn and HC1. NH 4 SH : black uranous sulphide, US. Alkalis : brown gelatinous uranous hydroxide U(OH) 4 . Alk. carbonates : green uranous hydroxide, sol. in excess. AuCl 8 , Ag-NOs : ppt. of Au or Ag. Ferric salts are reduced to ferrous salts. URANIC SAI/TS. Uranic salts are yellow. WET TESTS. Diss. o'i gm of Uranylic nitrate UO 2 (NO 8 ) 2 in 10 c.c. aq. NH 4 OH, KOH and NaOH : yellow ppt. of (NH 4 ) 2 U 2 O 7 , insol. in excess. NH 4 SH, in neutral .sols. : a dull yellow or brown ppt. of uranylic sul- phide, UO 2 S, precipitation is hastened by NH 4 C1, sol. in (NH 4 ) 2 CO 3 ; sol. in acetic and other acids. Boiled with NH 4 SH in excess it changes to black UO and S. (NH 4 ) 3 P04 : white ppt. H 2 S : no ppt. in acid sols. (NH 4 ) 2 C0 3 , Na 2 C0 3 and K 2 C0 3 : yellow ppt. of the double carbonates (e.g. , pot. uranic carbonate), readily sol. in excess, reprecipitated by boiling with NaOH, thus differing from Fe. K 4 FeCy 6 in acid sols. : reddish brown ppt. (Characteristic). BaCOs completely precipitates U in the cold ; hence it separates U from Ni, Co, Mn, Fe" and Zn. Zn and HC1 : a green colour, no ppt. Indium. In, 113-1. DRY TESTS. i. On charcoal : white ductile beads. 2. Flame test : bluish colour ; its spectrum shows a bright blue and pale violet line. In minerals. Extract with HC1, pour off the clear liquid after 24 hours and add a few drops of dil. H 2 SO 4 to the residue, wash thoroughly with hot GALLIUM AND VANADIUM 33 aq. ; add HNO* and a few drops of H 2 SO 4 , evaporate nearly to dry ness, add aq. and filter. Add NH 4 OH in large excess to filtrate, filter, wash ppt. and diss. in a very little HC1, add excess of NaHSO 4 and boil, when 2ln 2 O33$O 2 ,8H 2 O separates out. WET TESTS. Diss. *oi gm. of In. 2 3SO 4 in 5 c.c. aq. Alkalis : ppt. of In(OH) 3 , white and voluminous, insol. in excess. Alkaline carbonates : gelatinous ppt. of In 2 3CO 3 . SH - : no ppt. except in dil. and slightly acid sols. , but it is wholly pre- cipitated in the presence of acetic acid as yellow sulphide, In. 2 S 3 , sol. in boiling NH 4 SH, from which the white sulphide separates on cooling. NH 4 SH, tartarie acid and an excess of NH 4 OH : a white ppt. of In. 2 S 3 , turned yellow by acetic acid; sol. in hot 'NH 4 SH. Zinc and HC1 : metallic In. Gallium. Ga, 69-5. Occurs in certain zinc blendes, etc. Best sought for by aid of the spectroscope. Vanadium. V, 50-8. DRY TESTS. Blowpipe. Borax bead in outer flame, colourless or yellow ; in inner flame green, hot and cold. If much V be present the bead is brown hot and green when cold. WET TESTS. Diss. 0*1 gm. of Na metavanadate (NaVO 3 ) in 7 c.c. aq. NH 4 SH in excess : brown colour ; acidulate with H 2 SO 4 : brown ppt. of V 3 S S , sol. in NH 4 SH. H 2 S, H 2 SO. ? or H 2 C 2 4 in acid sol. : blue colour due to reduction of the vana- dates. With H. 2 S, S is also separated. Zn and dil. H 2 S0 4 , warm : blue, changing to green and lavender. NH 4 C1 cone, sol., or NH 4 OH and NH 4 C1 : white ppt. of (NH 4 ) 3 VO 4 . (Charac- teristic). H 2 2 in ether, shake with two drops of HC1 : red colour. Gallic acid : blue black colour, disappears with excess of reagent. K 3 FeCy 6 : light green ppt. In minerals. Boil with cone. HNO 3 , remove Pb by H 2 SO 4 and filter, wash ppt. with alcohol, the filtrate contains V 2 O 5 : confirm by Zn and HC1. 34 RUBIDIUM AND CESIUM THE RARER METALS OF GROUP VI. RUBIDIUM AND CESIUM. Kubidium. Rb, 84-8. Caesium. Cs, 132. DRY TESTS. (a) Both Rb and Cs salts impart a greyish colour to the flame. (&) The spectra afford the best tests. Rb gives two character- istic lines in the red and two in the blue ; Cs gives two light blue lines to the right of the Sr $ line. WET TESTS. Use sols, of RbCL 2 and CsCl,. RbCl-2 and CsCl, : ppt. with H,PtCl 6 and H.AHA similar to the Pt ppts. The Rb 2 PtCl (; and Cs. 2 PtCl 6 are less sol. in aq. than K 2 PtCl 6 , hence the latter can be washed out by boiling with successive small quantities of aq. REACTIONS OF THE ACIDS. INORGANIC ACIDS. Hydrofluoric Acid. HF. DRY TESTS. Most fluorides fuse, some give off HF gas, which attacks glass, all do when fused with KHSO 4 . Mix the powdered fluoride with KHSO 4 and heat strongly in a piece of hard glass tubing, wash and dry the tube to render the etching visible. [NOTE. Do not inhale the gas.] WET TESTS. Diss. '05 gm. of NaF or of NH 4 F in 3 c.c. aq. CaCl-2 : a transparent gelatinous ppt. of CaF. 2 , insol. in HF. H 2 S0 4 cone., warm : HF is evolved, rinse out the tube, dry it, and note the corrosion of the tube. BaCl 2 : white ppt. of BaF- 2 , sol. in HNO 3 and in HC1. H 2 S0 4 and sand warmed with a dry fluoride : SiF 4 , which deposits gela- tinous silicic acid on a moist rod lowered into the test tube. Hydrochloric Acid. HC1. DRY TESTS. Blowpipe. Chlorides heated in a microcosmic salt bead with a little CuO impart a vivid blue colour to the flame. Most chlorides fuse but some are decomposed on heating, e.g., AuCl 3 and PtCl 4 . H 2 S0 4 (cone.), warm : HC1 gas, which turns blue litmus paper red. NOTE. The cone. H 2 SO 4 test can usually be applied either to the solid salt or to its sol. WET TESTS. Diss. 'i gm. NaCl in 5 c.c. of aq. AgNO ;! : white curdy ppt. of AgCl which darkens on exposure to light. Insol. in HNO i( , sol. in NH 4 OH, KCy, etc. Fuses to a horny mass. H 2 S0 4 and Mn0 2 , warm : Cl, which bleaches litmus paper. K 2 Cr 2 07 (about 0*1 gm. in powder) and 2 c.c. of H 2 SO 4 , on warming with a dry chloride evolve red-brown vapours of chromyl chloride (CrO 2 Cl 2 ) which condense to a dark red liquid. Hypochlorous Acid. HC10. DRY TESTS. Hypochlorites when heated are converted into chlorides and chlorates. The CO 2 in the air decomposes them with evolution of chlorine, 35 36 CHLORIC ACID, PERCHLORIC ACID AND HYDROBROMIC ACID WET TESTS. Diss. ;i gm. NaCIO in 6 c.-c. of cold aq., or pass Cl into 6 c.c. cold dil. NaOH sol. Litmus, Indigo, etc., are bleached by aqueous solutions of hypo- chlorites. HC1 (dil.) : Cl, recognised by its odour and colour. MnSOi : is oxidized to brown MnO 2 ,H. 2 O. NiS0 4 : is oxidized to black Ni(OH) 3 . Pb(C 2 H 3 2 )2 : white ppt. of PbCL 2 , which gradually becomes yellow, orange and finally brown, due to its conversion into lead peroxide. Chloric Acid. HCl(k DRY TESTS. i. On ignition alkaline chlorates fuse and evolve oxygen, or a mixture of O and Cl. They deflagrate on char. Diss. the residue in aq., add AgNO 3 sol. : white ppt. of AgCl. 2.. When rubbed or heated with oxidizable substances, e.g., C, S, P, sulphides, or cyanides, they explode violently, also when H 2 SO 4 is added to such mixtures, or warmed with a chlorate ; due toCJP 2 . H 2 S0 4 , cone, heated with a small fragment of KC1O 3 : sharp detonation. [CAUTION. Use only one small fragment of KC1O 3 , about "003 gm. is sufficient.] HC1 : Cl and C1O 2 evolved. WET TESTS. Diss. 'i gm. KC1O 3 in 3 c.c. aq. All the chlorates are soluble. AgNO* : no ppt. H 2 S0 4 , cone. : CIO., (a greenish-yellow gas) is evolved and the solution becomes orange coloured, on warming : violent explosion. Indigo (and 2. drops of H 2 SO 4 ) becomes bleached. Perchloric Acid. HC10 4 . Perchlorates are more stable than chlorates ; they are decomposed by hot cone. H 2 S0 4 , but not by the cold acid. HC1 or HNO-? : no action. Hydrobromic Acid. HBr. DRY TESTS. -Most bromides, like chlorides and iodides, fuse without decomposition ; also when mixed with CuO and heated in the inner flame bromides impart a vivid blue colour to the flame. BROMIC ACID, HYDRIODIC ACID AND IODIC ACID. 37 Add H 2 SO 4 to a small crystal and warm : red vaps. of Br. WET TESTS. Diss. o'i gm. KBr in 4 c.c. aq. AgNO* : pale yellow, curdy ppt. of AgBr, insol. in HNO ;1 ; difficultly sol. in NH 4 OH, readily in KCy. H 2 S0 4 : HBr, Br and SO* evolved. H 2 S0 4 and MnO- 2 warmed with a bromide : dense red vaps. of Br. Cl aq. : brown colour due to the Br set free. Shake with CHC1 3 or CS 2 : brown sol. Bromic &cid. HBrO , DRY TESTS. All bromates arSJ!lecomposed on ignition, and like the chlorates deflagrate when mixediajBtth oxidizable substances. WET TESTS. Diss. '05 gm.^KBrO.-! in "2 c.c. aq. AgNOs : white AgBr() :1 , this with HC1 gives off Br. H<>S0 4 : bromic acid, which brealosVup into H 2 O, Br and O. \ Hydriodic Acid. HI. DRY TESTS. Most iodides on ignition give off I, but the alkaline iodides and Agl do not. WET TESTS. Diss. T gm. of KI in 9 c.c. aq. All the iodides are sol. in acids except Agl. Ag-NO;, : pale yellow Agl, nearly insol. in NH,OH and in dil. HNO 3 . Sol. in KCy, KI, NaCl, Na 2 S-O, and in HC1. Pb2C 2 H 3 02 : yellow PbI 2 , sol. in hot aq., redeposited on cooling. Hg-NOa : greenish ppt., Hgl. lo : yellow ppt. of HgI 2 changing to scarlet, sol. in KI and in HgCL 2 . i cone. : deep brown sol., due to I ; on warming yields purple vapours. H 2 S0 4 and Mn0 2 : purple vapours of iodine. Cu 2 S0 4 : grey Cul. The cuprous sulphate, Cu 2 SO 4 , can be prepared by adding SO,, FeSCX, or Na 2 SO. ? to CuSO,. Chlorides and bromides do not precipitate CuSO.,. Cl aq. (or Br aq., or dil. HC1 and a drop of KN0 2 sol.) and starch sol. : blue colour. Cl aq. (or Br aq.) and CS> or chloroform : purple solution. lodic Acid. HIO. DRY TESTS. All iodates decompose on ignition, some lose O and are converted into iodides, and others give off both I and O. They explode when heated with charcoal and other combustible substances. 38 SULPHURIC ACID, AND SULPHUROUS ACID WET TKSTS. Diss 'i gm. of KIO 3 in 5 c.c. aq. Only the alkali iodates are sol. in water. BaCL : white ppt. of Ba(IO 3 ) 2 , difficultly sol. in dil. HNO 3 . AgN0 3 : white ppt. of AgIO 3 , sparingly sol. in dil. HNO 3 , but readily in NH 4 OH. SH 2 : ppt. of S. HaSO-i : ppt. of iodine and S. KI, starch sol. and acetic acid : blue " iodide of starch." Used as a test for the presence of iodate in iodides. Sulphuric Acid. ILSOi. DRY TESTS. Blowpipe. Fuse the sulphate with pure Na 2 CO ; , on char, or on a charred match, in the reducing flame to convert the sulphate into Na 2 S, place the melt or fused mass on a brightened coin and moisten ; a brown or black stain will be produced. All sulphur compounds give this reaction. WET TESTS. Diss. 'i gm. of Na. 2 SO 4 in 2 c.c. of aq. BaCl 2 : heavy white ppt. of BaSO 4 , insol. in HNO 3 and NH 4 OH. Dil. solutions require to stand for some time. Pb2C 2 H 3 0; : heavy white ppt. (PbSO 4 ) insol. in HNO 3 , sol. in boiling cone. HC1, in KOH, NH 4 C 2 H 3 O, and Na 2 S 2 O 3 . Free H>S0 4 is recognised by evaporating it down on a water bath with a little cane sugar, or fragment of filter paper, which chars. Insoluble sulphates (e.g., BaSO 4 ). Boil with pure Na 2 CO 8 , or fuse with pure Na 2 CO 3 on Pt foil, dissolve the residue in water, filter off the carbonates formed, and test the filtrate with BaCl 2 as above. Sulphurous Acid. ILSOa. DRY TEST. On heating, some sulphites give off odour of burning S,(S0 2 > WET TESTS. Diss. '2 gm. of Na 2 SO 3 in 6 c.c. aq. BaCl 2 : white ppt. of BaSO 3 , soluble in strong HC1 ; if the ppt. is not entirely soluble in HC1 some H 2 SO 4 is present, filter off the BaSO 4 formed and to the filtrate add Cl water. If a second ppt. of BaSO 4 forms it is due to a sulphite which has been oxidised by the Cl to a sulphate. BaSO 3 becomes insol. in dil. HNO 3 from the formation of BaSO 4 . HC1 (dil.) : SO 2 is evolved. THIOSULPHURIC ACID AND HYDROGEN SULPHIDE 39 AgNOs : white Ag. 2 SO 3 , sol. in excess of Na. 2 SO n ; add a drop of H.SOi and warm : metallic Ag. KMnCh with a drop of H^SOi is reduced and decolourised (very delicate). K. 2 Cr0 4 sol. and 2 drops HC1 : green colour. FeCls : red colour ; on boiling : ppt. of brown basic salt. (Distinction from thio-sulphates.) Thiosulphuric Acid. ILS-Ck Only known in combination. Most thiosulphates are sol. in water. DRY TESTS. All thiosulphates are decomposed on ignition, some fuse and the S burns. WET TESTS. Diss. "5 gm, Na 2 S 2 O 3 in 4 c.c. aq. HC1, warm : SO. 2 is evolved and S deposited. AgNOs : white ppt. of Ag thiosulphate (AgfSO t ), which quickly passes into black Ag 2 S. FeCLs : violet colour which gradually fades. Zn and HC1 : SH. 2 and ppt. of S, the nascent hydrogen generated reduces the H,S 2 O 3 . Hydrogen Sulphide (Sulphine). SH 2 . DRY TESTS. i. Ignition tube. Many metallic sulphides heated in a bulb tube evolve SO- and yield a sublimate of free S. AsaS s and HgS sublime undecomposed. 2. Roasting tube. Heated in an open tube sulphides evolve SO. 2 . 3. On char, before the blowpipe : SO. 2 , and sometimes the flame of burning S. WET TESTS. Only the sulphides of the alkalies and of Sr and Ba are soluble in aq. ; Ca and Mg sulphides are sparingly soluble. Diss "i gm. Na. 2 S in 3 c.c. aq. and filter off the separated S. HC1 (dil.) : SH. 2 gas evolved from above and from FeS, MnS, and ZnS ; on heating the sol. S separates. SH 2 can be recognised by its odour. [NOTE. All the sulphides except those of Ag, Hg, Pt, Au and As evolve SH. 2 with strong HC1]. Paper moistened with Pb. acetate sol. is blackened by SH 2 gas. HNO.i (strong) : converts Bi. 2 S 3 , CuS, Ag 2 S, PbS, As. 2 S 3 into sulphates and free S. SnS. 2 , Sb>S 3 and As. 2 S 3 are converted into SnO. 2 , Sb 2 O 4 and H 3 AsO 4 . SbCls sol. : orange Sb 2 S 3 . 40 NITRIC ACID AND NITROUS ACID Na. nitroprusside Na. 2 FeNOCy> : purple colour with even traces of soluble sulphides, no colour with free SH. 2 . [NOTE. To prepare Na 2 FeNOCy 5 , warm 5 c.c. of strong HNO ;( with 5 gm. of K 3 FeCy fi in a test tube, dilute and neutralize with Na. 2 CO 3 .] Nitric Acid. HN(k DRY TKSTS. On ignition most nitrates fuse and give off red fumes ; they deflagrate when heated with oxidizable substances such as organic matter, charcoal, sulphides and alkaline cyanides. WET TESTS. Diss. '2 gm. of NaNOs in 5 c.c. aq. Cu foil and H 2 S0 4 , warm : red fumes of NO 2 , FeS0 4 , add a crystal and 4 drops cone. H 2 S0 4 : brown colouration around the crystal, due to the evolution of NO and its solution in FeSO 4 . H 2 S0 4 cone. '5 c.c. then carefully pour a solution of FeS0 4 on to the top : brown ring. Diss. a particle of Brueine in one drop of cone. H 2 SO 4 on a watch glass, add a drop of NaNO ;? sol. and stir : deep red colour. Indigo and H 2 SOi (cone.) : the blue colour changes to yellow (isatin). To detect free nitric acid in the presence of a nitrate, warm the mixture on a water bath with white wool or silk or with small pieces of quill ; a yellow stain shows the presence of free nitric acid. Nitrous Acid. HNO. DRY TEST. On ignition nitrites fuse, yield oxides, and give off N and O. Mixed with oxidizable bodies they deflagrate like the nitrates. WET TESTS. Diss. 'i gm. of KNO 2 in 6 c.c. aq. FeS0 4 and H 2 S0 4 (cone.) : a brown colour. (See HNO 3 ). HgN0 3 is reduced to metallic Hg on warming. Indigo in H 2 SO 4 : yellow isatin. KI and starch solution and acetic acid : blue colour ; sensitive to i in 10 millions. (See iodides). Sulphanilie acid and napthylamine- Diss. equivalent weights of these in H 2 SO 4 and add i.c.c. of the mixture to i c.c. of the above nitrite sol. diluted to 100 c.c. : rose colour. It is said to detect i of HNO 2 in 10,000,000 of aq. Meta-phenylenediamine hydroehloride and HC1 one drop : yellow to brown (i in 250,000). To detect nitrates in the presence of nitrites. Destroy the nitrite by boiling with urea and H 2 S0 4 , or with NH 4 C1, when the nitrate may be detected by the FeSO 4 , or Cu tests. SILICIC, HYDROFLUOSILIC, BORIC, METABORIC AND PYROBORIC ACIDS 4! Silicic Acid, ILSiCX. Silica, Si(k DRY TESTS. Blowpipe. Infusible; with Na 2 CO 3 : clear glass. Sili- cates fused in microcosmic bead : floating skeleton of SiO 2 . Silica and all silicates except those of Na and K are practically insol. in water. WET TESTS. Fuse "2 gm of SiO 2 in -5 gm. of Na 2 CO 3 on Pt foil : clear glass of Na 2 SiO 3 ; diss. the result in 10 c.c. boiling aq., and use it for the following experiments. HC1 (dil.) when neutral : ppt. of gelatinous H 4 SiO 4 ; evaporate 5 c.c. to dryness, the dry product (SiO 2 ) is now insol. in water and in acids. AgNOs : orange ppt. of Ag 2 SiO 3 , sol. in acids and NH 4 OH. NH 4 C1 and (NH 4 ).2C0 3 : ppt. of H 4 SiO 4 . HF decomposes most silicates ; pass the resulting SiF 4 into aq. : gelatin- ous H 4 SiO 4 . Silicates which are insoluble in acids. Finely powder and fuse the silicate with Na 2 CO 3 and K 2 CO 3 on Pt foil ; extract the Na and K silicates with hot water, filter off the metallic carbonates ; acidify the filtrate with HC1 and evaporate to dryness, extract with hotaq., residue : SiO 2 . Silica is usually detected in the examination for bases. Hydrofluosilicic Acid (Fluosilicic or Silicofluoric Acid), DRY TESTS. Silicon* uorides on ignition : fluorides and SiF 4 . Heated with H 2 SO 4 , HF is evolved. WET TESTS. Diss. 'i gm. of (NH 4 ) 2 SiF G in 4 c.c. aq., or use a solution of the acid itself. BaCl 2 : crystalline ppt. of BaSiF 6 . Hastened by adding an equal vol. of alcohol. SrCl 2 : no ppt. KC1 : gelatinous K 2 SiF 6 . NH 4 OH : gelatinous H 4 SiO 4 . Boric acid, H 3 B(k Metaboric Acid, HB0 2 , Pyroboric Aci All the alkali borates are readily soluble in aq., the others sparingly ; all are soluble in acids. DRY TESTS. Blowpipe. (a) Many borates intumesce (i.e., boil up) when heated, and yield a colourless glass. (&} Mixed with KHSO 4 and fused on Pt. wire : green flame, (c) For traces of boron mix the substance with KHSO 4 and CaF 2 , and fuse on Pt wire : green colour, due to BF 3 . 4 2 PHOSPHORIC ACID WET TESTS. Diss. 'I gm. of borax (Na 2 B 4 O 7 .ioH 2 O) in 6 c.c. aq. H 2 S0 4 cone. : scales of H 8 BO 3 (from strong solutions only). Turmeric paper dipped into the solution : brown colour. Cureumine (or turmeric) and oxalic acid. Dry on water bath : magenta colour, on adding NaOH it changes to blue. If not already free, set the boric acid free by two drops of HC1 or H. 2 SO4. BaCl 2 : white ppt. of BaB 2 O 4 forms slowly ; sol. in acids. AgN0 3 : white (Ag 3 BO 3 ) sol. in HNO 3 and in NH 4 OH, sol. becomes black on boiling. H 2 S0 4 cone, orglyeerol, make into a thin paste with a borate and warm, add to a little spirit and ignite : green edged flame. Phosphoric Acid (Orthophosphoric Acid). ILPCh. DRY TESTS. Blowpipe. Normal metallic phosphates are not decom- posed on ignition ; those containing H lose H 2 O and are converted into pyro and metaphosphates. Most phosphates are decomposed on fusion with K 2 CO 3 and Na 2 CO 3 , the phosphates of Ba, Sr and Ca are only partly decom- posed ; in the case of A1PO 4 , add SiO 2 to the fusion mixture. Most dry metallic phosphates, when heated with Mg or Na in a tube, or fused by the blowpipe with dry Na 2 CO 3 on char., or with the match test, are reduced to phosphides, and these emit phosphine (PH 3 ) when moistened with water. Phosphates heated with Co2NO 3 : blue colour. On heating orthophosphoric acid it loses water and yields pyrophos- phoric acid, and finally metaphosphoric acid. WET TESTS. Diss. 'i gm. of Na 2 HPO 4 in 6 c.c. aq. BaCl 2 : white ppt. of BaHPO 4 , sol. in HNO 3 and in HC1, difficultly sol. in NH 4 C1. CaCl 2 : white ppt. of Ca 3 P 2 O 8 , sol. in HC 2 H 3 O 2 . MgCl 2 + NH 4 C1 + NHUOH : crystalline ppt. of MgNH 4 PO 4 .6H 2 O, especially on stirring or shaking ; insol. in NH 4 OH, sol. in acetic acid. (See arsenic acid). AgN0 3 : yellow ppt., Ag B P(X, sol. in HNO 3 and in NH 4 OH. (NH 4 ) 2 Mo0 4 in HN0 3 cone, and warm : yellow crystalline ppt. of ammonium phospho-molybdate, (MoO 3 ) 12 (NH 4 ) 3 PO 4 . (?) FeCl 3 : yellowish gelatinous ppt. of FePO 4 , somewhat sol. in excess of FeCl 3 , sol. in HC1. Arseniates also give a yellow ppt., hence if present they must be reduced by SO 2 and removed by SH 2 . (See also ' ' phosphates ' ' table.) PYROPHOSPHORIC ACID, ETC 43 Pyrophosphoric Acid (ILPaOT) and Metaphosphoric Acid (HPOs). Both give white ppts. with AgNO 3 , metaphosphates (with acetic acid) co- agulate "albumen, pyrophosphates do not. They do not give ppts. with (NH^MoCX in the cold, but on boiling they are converted into orthophosphoric acid, which gives a ppt. [NOTE. Pyrophosphates and metaphosphates are converted into ortho- phosphates during the process of analysis, hence they must be sought for by special methods.] Phosphorous Acid. ILPCk DRY TESTS. Phosphites decompose and ignite when heated on Pt. foil. Heated in a tube they evolve H and PH 3 , and are converted into phosphates. Phosphites of the alkalies are soluble in water. WET TESTS. Diss. T gm. Na 2 HPO 3 in 4 c.c. aq. AgNOs : metallic silver ; the reduction is aided by NH 4 OH and warming. HgCh : HgCl and Hg. Zn and HC1 : H and PH 3 , the gas burns with a green colour and blackens filter paper moistened with AgNOs, due to the formation of Ag 3 P and metallic Ag. SO-2 is reduced to S, and SH 2 is evolved. The phosphite is oxidized to phosphate. Hypophosphorous Acid. HP0 2 DRY TEST. On ignition hypophosphites evolve PH 8 , and are con- verted into pyrophosphates, M' 4 P 2 O7. WET TESTS. Diss. 'i gm. NaH 2 PO 2 in 5 c.c. of aq. H 2 S04 is reduced to H 2 SO 3 and S (on warming). AuCls, AgN0 3 and CuS0 4 are reduced to metals. - Zn and H 2 S0 4 : H and PH 3> with garlic odour. v^r Carbonic Acid. ILCOs. DRY TESTS. On ignition, alkali carbonates fuse without decomposition, at high temperatures they volatilize ; the others decompose into CO* and oxide of the metal, or CO 2 , O and the metal. WET TESTS. Diss. 'i gm. Na 2 CO 3 in 5 c.c. aq. HC1 : effervescence, a rod or tube which has been dipped into lime water and lowered into the escaping gas becomes coated with CaCO 3 ; the gas extinguishes a taper. Native MgCO 3 , CaMg(CO 8 ) 2 and FeCO 8 are very slowly decomposed by cold HC1. BaCl 2 : white ppt. of BaCO 3 which dissolves in dil. HC1 with effer- vescence. 44 HYDROCYANIC AND CYANIC ACIDS ORGANIC ACIDS. Hydrocyanic Acid. HCN or HCy. DRY TESTS. Blowpipe. (a) KCy and NaCy fuse when heated and gradually oxidize to cyanates (M'CNO) ; cyanides of the heavy metals are decomposed and cyanides of Au, Hg, Ag, etc., yield free cyanogen (CN) a or Cy 2 and brown paracyanogen Cy n ; Na, K, Hg and Ba cyanides are sol. in aq., those of Ag, Cd, Co, Cu, Ni and Zn are not. (d) Fuse with a particle of Na 2 S 2 Os in a Pt ring until the S flame appears, place the bead in a sol. of Fed* : a red colour of Fe(CyS) 8 . (c) Fuse a cyanide with KOH : NH 3 . WET TESTS. Diss. 'i gm. KCy in 6 c.c. aq. The cyanides of the alkalies emit the odour of HCy, from the action of CO 2 and H 2 O in the air. HC1 (dil.) : HCy. Do not inhale, as HCy is intensely poisonous. Test the odour with great care by wafting the fumes towards the nose with the hand. Certain double cyanides also evolve HCy, e.g., KCy, AgCy -\- HNO 3 = AgCy + HCy + KNO 3 ; but other double cyanides do not, e.g., K 4 FeCy 6 -f 4HC1 = H 4 FeCy fi (Ferrocyanic acid) + 4KC1. 2K 3 FeCy 6 + 6HC1 = 2H 3 FeCy 6 (Ferricyanic acid) + 6KC1. 2KCoCy 6 + 6HC1 = 2H 3 CoCy 6 (Cobalticyanic acid) + 6KC1. Ag-N0 3 : white curdy ppt. of AgCy, insol. in dil. HNO 3 ; sol. in NH 4 OH, Na 2 S. 2 O 3 and in excess of KCy. On ignition : metallic Ag (AgCl fuses). If AgCy and AgCl are both present, wash, ignite, dissolve out the metallic Ag by HNO 3 , and add HC1 : ppt. of AgCl. Add dil. H 2 S0 4 to a cyanide in a watch glass and invert over it another watch glass moistened inside with yellow NH 4 SH, in a few minutes NH 4 CNS is formed, evaporate this nearly to dry- ness over a water bath and add a drop of FeCl 3 sol. : a blood red colour. HgN0 3 : grey ppt. of Hg. FeS0 4 , FeCl 3 and HC1, on warming : ppt. of Prussian blue. NaN0 2 and FeCl 3 and dil. H 2 S0 4 until the colour is yellow ; warm gently, cool, add NH 4 OH and filter, then one drop NH 4 SH : violet colour ; due to Na nitroprusside. Cyanic Acid (Carbimide). HCyO. Pot. cyanate, KCNO, is formed by the oxidation of KCy. KCyO deliquesces and smells of NH 3 . KCNO -f 2H 2 O = KHCO 3 + NH 8 . The cyanates of the alkalis, alk. earths and some others are sol. in aq., the solutions decompose and evolve NH 3 . On warming the sol. of Am. cyanate it changes into urea, NH 4 CyO : (NH 2 ) 3 CO. HYDROFERROCYANIC AND HYDROFERRICYANIC ACIDS 45 DRY TESTS. On ignition, many of the cyanates of the heavy metals evolve CO 2 and form cyanides. WET TESTS. Diss. '05 gm. KCyO in 2 c.c. aq. HC1 : pungent odour of HCyO, irritates the eyes. AgNOs : white ppt., AgCyO, sol in NH 4 OH and in dil. HNO 3 . Hydroferrocyanic Acid. ILFeCeNe or H 4 FeCy 6 . DRY TESTS. On strong ignition some fuse and yield N, M'Cy, Fe, iron carbide, and some M'CyO ; thus K 4 FeCy 6 : 4KCy + 2C + Fe -f N 2 . The alk. ferrocyanides are sol. in aq., those of Ba, Sr, and Ca, sparingly sol. ; most of the others are insol. in aq., and some are insol. in acids. WET TESTS. Diss. 'i gm of crystallized K 4 FeCy 6 in 7 c.c. aq. H 2 S0 4 (cone.) : CO evolved. H 2 S0 4 (dil.) : HCy evolved. HC1 (cone.) : white ppt. of H 4 FeCy 6 , changes to blue. Ag-NOs : white ppt. Ag 4 FeCy 6 sol. in KCy but insol. in dil. HNO 3 and in NH 4 OH. CuS0 4 , in excess : chocolate ppt. of Cu 2 FeCy 6 . FeS0 4 : pale blue ppt. of pot. ferrous ferrocyanide K 2 Fe(FeCy 6 ) which rapidly oxidizes to ferric ferrocyanide (Prussian blue) Fe 4 (FeCy6) 3 . FeCl 3 : Prussian blue, insol. in dil. mineral acids, but sol. in oxalic acid ( : blue ink) and ammonium tartrate ( : violet- ink). [NoTE. This is also a test for tartrates.] If insufficient FeCl 8 is added this ppt. is sol. in aq., known as soluble Prussian blue, also used as a blue ink. Prussian blue is decomposed by alkalis. Fe 4 (FeCy 6 ) 3 + I2KOH = 3K 4 FeCy 6 + 4Fe(OH) 3 i.e., the cathion iron is precipitated but not that in the anion. Hydroferricyanic Acid. H 3 Fe(CN) 6 or H 3 FeCy 6 . Ferricyanides can be obtained by oxidising ferrocyanides with Cl, etc. DRY TESTS. On heating, K 3 FeCy 6 evolves N and Cy, and leaves a residue of paracyanogen, carbon, iron carbide and Prussian blue. The alkali ferricyanides are sol. in water, most of the others are not. WET TESTS. Diss. 0*1 gm. of K 3 FeCy 6 in 3 c.c .aq., or add Cl water to 3 c.c. K 4 FeCy 6 solution. AgN0 3 : reddish ppt. of Ag 3 FeCy 6 , sol. in NH 4 OH and in KCy, insol. in dil. HNO 3 . FeS0 4 : blue ppt. of ferrous ferricyanide, Fe s (FeCy6) 2 (Turnbull's blue), decomposed by KOH. FeCls ' brown or green colour. 46 THIOCYANIC, FORMIC AND ACETIC ACIDS Thiocyanic Acid (Sulphocyanic Acid). HCNS or HCyS. DRY TESTS. KCyS on ignition is converted into KCyO, K. 2 SO 4 and SO a . The thiocyanates of the heavy metals evolve CS 2 , N and CN, and leave a metallic sulphide. WET TESTS. Dissolve "01 gm. NH 4 C) T S or KCyS in 3 c.c. aq. Ag-N0 3 : white curdy ppt. of AgCyS, sol. in NH 4 OH, but insol. in dil. acids. CuS0 4 (2 drops) : black ppt. of Cu(CyS) 2 . If the CuSO 4 is in excess there is no ppt. FeCl 3 : blood red coloured sol. of Fe(CyS) 3 , on adding Zn to the red sol. SH 2 is evolved. HgCl a discharges this colour, HC1 does not. Formic Acid. H.COOH. Fuming liquid, with pungent odour, boils 99 C., mixes with H 2 O, alcohol, and ether. Its salts are readily sol., except Pb formate; the salts (and the free acid) are strong reducing agents. DRY TESTS. Solid formates when heated char slightly, and evolve CO and CO 2 . WET TESTS. Diss. 'oi gm. Na formate, NaCHO 2 , in 7 c.c. aq. H 2 S0 4 , dil. : formic aoid is evolved, recognised by its odour and by its blackening paper moistened with AgNO 3 . H 2 S0 4 cone, decomposes formic acid and the formates, and CO is evolved. H 2 S0 4 and alcohol : formic ether (odour of rum). AgN0 3 , warm : black ppt. of Ag. HgCl 2 , warm : white ppt. of HgCl or of grey metallic Hg. FeCls : red colour (like acetates) destroyed by the addition of HC1 ; on boiling, basic ferric formate is precipitated and the liquid becomes colourless. KMn0 4 sol., is reduced by formic acid. Acetic Acid. CIL.COOH. A colourless pungent acid liquid, crystallizes at i6'5 and boils at 118, its vapour burns with a bluish flame. Mixes with water, alcohol, and ether in all proportions. DRY TESTS. Acetates on ignition give off acetone and other inflam- mable vapours and leave a carbonate, oxide, or metal. Dry acetates heated with a little As 2 O 3 (use *oi gm.), give off Cacodyl As(CH 3 ) 2 (or cacodyl oxide, (CH 3 As) 2 O), recognised by its offensive odour. [N.B. This is extremely poisonous. Caution. Never apply the test tube to PROPIONIC, BUTYRIC AND OXALIC ACIDS 47 the nose when testing by odour, always waft the vapour from the test tube towards the nose by the hand, or cover the mouth of the test tube with a piece of filter paper, remove the paper after a few moments and ascertain whether it has acquired any odour]. WET TESTS. Diss. '2 gm. Na acetate (NaC 2 H 3 O 2 ) in 4 c.c. aq. H 2 S0 4 (either dil. or cone.) : odour of " vinegar," i.e., of acetic acid. H 2 S0 4 and alcohol on warming : ethereal odour of ethyl acetate. AgN0 3 , in strong solutions : white crystalline Ag acetate ; not reduced on boiling. (Distinction from formic acid.) FeCls in neutral sols. : dark red colour, destroyed by HC1 ; on boiling a ppt. of basic ferric acetate forms and the solution becomes colourless. Propionic Acid. C 2 H 5 .COOH. Has the odour of rancid butter and of acetic acid. Occurs in sour cocoanut milk, oil of amber, and in certain wines when the fermentation has gone too far. Propionates are sol. in aq. If the free acids (formic, acetic, and pro- pionic) are evaporated to dryness with PbO and extracted with cold aq. and filtered, the Pb acetate and Pb formate will be found in the residue and the Pb propionate (basic) in the solution. Butyric Acids. C 3 H7.COOH. The normal acid, C 3 H 7 .COOH, has a strong and characteristic odour ; b.p. 163 C. The iso-butyric acid (CH 3 ). 2 CH.COOH, boils at 150, otherwise it closely resembles the former. Both are sparingly sol. in water. Can be separated from aqueous solution by agitating with ether and then evaporating. All the butyrates are sol. in H 2 O. WET REACTIONS. Diss. 'i gm. of Na butyrate in 6 c.c. aq. H 2 S0 4 , warm : odour of butyric acid. H 2 S0 4 and alcohol : ethyl butyrate, C 2 H 5 .C 4 H7O2, odour of pine apples (best test). AgNOs : white ppt. of AgC 4 H 7 O 2 . FeCl 3 : reddish brown sol. Cu acetate, with strong solutions : bluish-green oblique crystals. Pb acetate : white ppt., becoming oily on warming. Oxalic Acid. (COOH) 2 . Crystallizes in rhombic prisms (COOH) 2 .2H 2 O, which lose H a O and effloresce. Intensely poisonous. The normal oxalates of the alkalis are sol. in aq. , most of the others are not. 48 TARTARIC ACID DRY TESTS. On heating in a tube it yields aq. and sublimes, part is decomposed into CO, CO 2 and formic acid. On ignition alk. oxalates give off CO, blacken slightly and leave a car- bonate; oxalates of the alk. earths give off CO and CO 2 , and leave a carbonate which at high temps, is converted into M"O. H 2 S0 4 (cone.), warm, oxalic acid and oxalates decompose into CO and CO 2 without blackening. Test for CO 2 by CaO 2 H 2 on the end of a glass rod. WET TESTS. Diss. '2 gm. of (NH 4 ) 2 C 2 O 4 in 4 c.c. aq. CaCl 2 : white ppt of CaC 2 O 4 , sol. in HC1 or HNO 3 , almost insol. in KOH, NH 4 OH, oxalic and acetic acids. SpCl 2 , with neutral oxalates : a white ppt. of SrC 2 O 4 , insol. in acetic acid and in boiling aq. (Distinction from tartaric and citric acids.) AgN0 8 : white ppt. of Ag 2 C 2 O 4 , sol. in dil. HNO 3 and NH 4 OH. KMn0 4 (add H 2 S0 4 ) is reduced and decolourized on warming. N.B. Use a very weak sol. of KMnO 4 . Tartaric Acid. (CH.OH) 2 (COOH) 2 . Large colourless crystals, very sol. in aq., sol. in alcohol. The normal salts of the alkalis are readily sol. in aq., but the acid salts of K and NH 4 are only slightly soluble. DRY TESTS. On heating, tartaric acid and tartrates evolve odour of caramel ; the tartrates of the alkalis and alk. earths leave a carbonate mixed with carbon, the tartrates of the heavier metals leave the metal or its oxide mixed with carbon. H 2 S0 4 (cone.), warm, blackens, with evolution of CO, CO 2 , and SO 2 . WET TESTS. Diss. '5 gm. tartaric acid in 5 c.c. aq. KC1, stir and let stand for some time : crystalline ppt. of KHC 4 H 4 O 6 with an acid tartrate or free tartaric acid, but boric acid prevents the precipitation ; insol. in acetic acid, readily sol. in HC1, HNO 3 , H 2 SO 4 , alkalis and alk. carbonates. Ca0 2 H 2 (in excess) with free tartaric acid : white ppt. of Ca tartrate, sol. in NaOH and acetic acid. FOR NEUTRAL TARTRATES. Diss. '5 gm. NH 4 KC 4 H 4 O 6 in 5 c.c. aq. CaCl 2 , with neutral sols, of tartrates : white ppt. of CaC 4 H 4 O 6 , stir and let stand ; sol. in free tartaric acid. AgN0 3 : white curdy ppt. of Ag 2 C 4 H 4 O 6 , sol. in excess of the tartrate, in NH 4 OH and in HNO 3 . Partially dissolve some of the Ag 2 C 4 H 4 O 6 ppt. in dil. NH 4 OH, add a fragment of AgNO n , immerse the test tube in a beaker of warm water (about SUCCINIC ACID AND MAUC ACID 49 60 C) for 10 to 20 minutes; the Ag is reduced and forms a mirror on the test tube. A little free NaOH is said to hasten the formation of the mirror. N.B. Clean the test tube before using with NaOH and distilled aq. TO DISTINGUISH BETWEEN CITRIC AND TARTARIC ACIDS. Resorein and about 2 c.c. cone. H 2 SO 4 added to a very small quantity of a solid tartrate or tartaric acid, and carefully warmed : bright red colour. Pyrogallol, instead of resorcin : purple. FeS0 4 , a few drops of H 2 2 and an excess of NaOH : blue to purple colour. Citric acid does not give the above colour reactions. Succinic Acid, C 2 H4(COOH) 2 . Crystallized; readily sol. in water, alcohol, and ether, insol. in chloro- form. Benzoic acid is soluble. DRY TESTS. When heated in a tube it yields water and the anhydride sublimes, emits irritating vapours and causes coughing. Solid succinates when warmed with KHSO 4 yield succinic acid in oily drops, which crystallize on cooling. WET TESTS. Diss. '05 gm. of ammonium succinate in 3 c.c. aq. BaCl 2 : ppt. of Ba succinate on stirring. Add alcohol if the solution be dilute. Benzoates do not yield a ppt. with BaCl 2 . FeCl 3 : pale brownish ppt. of basic ferric succinate, sol. in acids. Pb(C 2 H 3 2 ) 2 ; white amorphous ppt. , sol. in excess of either the succinate or Pb acetate ; Pb succinate crystallizes out on standing. Malic Acid. C,Ha(OH)(COOH) 2 . Crystallized ; readily sol. in aq. and in alcohol. DRY TESTS. Heated in a tube it yields aq. and a crystalline sublimate of maleic and fumaric acids; at higher temperatures it emits odour of caramel, chars and evolves CO and CO 2 . WET TESTS. Diss. "05 gm. of Na malate in 3 c.c. aq. CaCl 2 : white ppt. of CaCJr^O.^HsO, on boiling or adding 2 vols. alcohol. Pb acetate : a white ppt. , which fuses on warming the liquid. AgNOa : a white ppt., becoming grey on boiling. 50 CITRIC ACID, LACTIC ACID AND BENZOIC ACID Citric Acid. CsIUOHXCOOH).,. Crystallized ; readily sol. in aq. and in alcohol. DRY REACTIONS. On heating in a tube citric acid yields aq. of crystal- lization, fuses and gives off irritating fumes (aconitic and citraconic acids and anhydrides) and leaves a residue of carbon. Citrates of the alkalis and alk. earths leave a carbonate. WKT TESTS. Diss. -5 gm. NagCoH-A in 5 c.c. aq. Ca0 2 H 2 : a white ppt. of Ca citrate, on boiling or long standing. (Differ- ence between citric and tartaric acids). CaCl 2 : a white ppt. on long standing or boiling, in neutral or alk. sols. ; insol. in NaOH, but sol. in NH 4 salts and in acids. AgN0 3 : white ppt. of Ag 3 C 6 H 6 O7, sol. in NH 4 OH, the sol. on boiling is reduced to metallic Ag (grey or black) but does not form a mirror. (See tartaric acid.) H 2 S0 4 (cone.) on warming, CO and CO 2 are evolved ; on boiling, the sol. slowly darkens and SO 2 is evolved. Lactic Acids. (a) Fermentation or ordinary laetie aeid, CH 3 .CH.OH.COOH., optic- ally active. (b) Sareo-laetie, optically inactive. (c) Ethene-laetie aeid : CH 2 OH.CH 2 .COOH. All three are syrupy inodorous liquids ; sol. in aq., alcohol and ether. DRY TESTS. At 150, a and b lactic acids lose water and emit irri- tating vapours of the anhydrides. WET TESTS. Diss. '2 gm. Na lactate in 5 c.c. aq. H-SOi (dil.) warm : acetaldehyde and formic acid. H 2 S0 4 (cone.) : CO evolved. Fehling's solution : not reduced. Ca 8 (P0 4 ) 2 (if recently precipitated) is dissolved by lactic acid. AgN0 8 is reduced by boiling with lactic acid. AROMATIC SERIES. Benzoic Acid, CH 5 .COOH. Crystallized in needles or plates, slight aromatic odour. Sparingly sol. in cold aq., more sol. in hot, readily in alcohol, ether, chloroform, alkalis, etc. Most benzoates are sol. in aq. SAUCYUC ACID AND GAWJC ACID 51 DRY TESTS. Melts at 121*4 C., volatilizes with irritating fumes. Yields sublimate of feathery crystals ; burns with smoky flame. Benzoic acid and solid benzoates heated with CaO yield benzene, C 6 H 6 . WET TESTS. Diss. "05 gm. Na benzoate in 5 c.c. aq. H 2 S0 4 : ppt. of white crystals (ben zoic acid). H 2 S0 4 and alcohol, aromatic odour of benzoic ether, C 2 H 5 .C7H 5 O2. FeCl 3 , in neutral sols. : buff ppt. of basic ferric benzoate, sol. in NH 4 OH. Pb acetate : flocculent ppt. of Pb(C 7 H 5 O 2 ) 2 .H 2 O, from fairly strong sols., sol. in Pb. acetate and in acetic acid. H 2 S0 4 and a fragment of Mg : odour of benzaldehyde, C 6 H 5 .CHO. Salicylic Acid. CeELOH.COOH. Crystallized ; slightly sol. in cold, more sol. in hot aq., sol. in alcohol, ether and alkalis. DRY TESTS. Melts 155 C. ; sublimes at higher temps., giving off phenol and CO 2 . Distilled with CaO it yields phenol. WET TESTS. Diss. "05 gm. of Na salicylate in 8 c.c. of aq. H 2 S0 4 (dil.) : crystalline ppt. of salicylic acid. H 2 S0 4 and methyl alcohol, warm : odour of oil of winter green (methyl salicylate). H 2 S0 4 (cone.) containing a few drops of 6 per cent. sol. of KN0 2 yields on warming a permanent red colour (phenol : a fleeting red). NaN0 2 , two drops ; acetic acid, four drops, and two drops of a dil. sol. of CuS0 4 , boil : intense red colour. AgN0 3 : white ppt. of Ag salicylate (but not with the free acid). HgN0 3 and HN0 3 (Millon's reagent), boil : red colour. FeCls : violet colour, destroyed by alkalis and by mineral acids, not destroyed by acetic acid. (Distinction from phenol.) Br water : white cryst. ppt. of tribromo-salicylic acid. Gallic Acid. C 6 H 2 (OH) 3 .COOH. Yellowish acicular crystals ; astringent taste ; readily sol. in hot aq. , sol. in alcohol, but sparingly in ether. DRY TESTS. On heating, it melts, CO 2 is evolved and pyrogallol sublimes. H 2 S0 4 (cone.), heat for two or three minutes : green sol., changing to claret or purple. WET TESTS. Boil '02 gm. with 10 c.c. aq. 52 TANNIC ACID AND PYROGAUJC ACID KOH, one drop, warm : bright green, changed to red by acids. CaCUSa : white ppt. changing through blue, green and violet to purple. FeSO* : pale blue colour. FeCls (dil.) : dark blue ppt., sol. in excess to a green solution. Gelatin solution ' no ppt. It is distinguished from tannin by not being pptd. from aqueous sol. by acids, by cinchonine sulphate or by gelatine. KCy : crimson, fleeting, but reappears on shaking. Pb2NOs : no ppt., compare tannic acid. Fehling's solution : slowly reduced on boiling. Tannic Acid (Digallic Acid, Gallotannic Acid, Tannin). CuHio0 9 . A buff or colourless powder, astringent taste, readily sol. in aq. and in alcohol, less sol. in ether. Acids precipitate it from aqueous solutions. DRY TESTS. On heating, tannin melts, blackens and yields H 2 O, CCV, and pyrogallol, the last condenses in yellowish drops and crystallizes on cooling. H 2 S04 ' red colour. WET TESTS. Diss. '02 gm. in 10 c.c. of aq. NaOH in excess : a brown colour changing to red and then to yellow. FeCls with neutral sols. : a blue-black ppt. (ink). Gelatin sol. : stringy ppt. (leather) ; gallic acid and pyrogallol do not coagulate gelatine. KCy, shake : brown-red colour. K 3 FeCyr, and NH 4 OH : deep red colouration. Pb2NOs : white ppt. of Pb tannate. (Distinction from gallic acid and pyrogallol.) Fehling-'s solution : reduced on boiling. Pyrogallol, Pyrogallic Acid. Cr,H.s(OH) 3 . Acicular colourless crystals; poisonous. Melts 131, boils 210; very sol. in water, alcohol, and ether, less sol. in chloroform and benzene. DRY TESTS. Heated in tube : black mass sol. in alkalis. H 2 S0 4 (cone.) : colourless sol., darkens on heating. NaOH or KOH : solution, which rapidly darkens from absorption of oxygen. WET TESTS. Diss. *02 gm. pyrogallol in 8 c.c. aq. Tartarie acid, and i c.c. cone. H 2 S0 4 , warm : violet colour. MKCONIC ACID AND URIC ACID 53 FeCla : green colour* FeS0 4 ' bright blue colour. Ca0 2 H 2 ' purple colour, changing to brown. Fehling's solution : red ppt. of Cu 2 O. Ag-NOs : ppt. of metallic silver. Formaldehyde, 2 drops, and 2 drops (cone.) H 2 S0 4 : white ppt., changing to. red and purple. Meconic Acid. Occurs in opium,* as morphine meconate. Colourless rhombic prisms or in plates ; readily sol. in alcohol and in hot water, sparingly sol. in cold aq. DRY TESTS. Heated in 1 tube at 100 C. : water; at 120 : CO 2 and comenic acid (C G H 4 O5) and at higher temps. : chars and emits odour of caramel. WET TESTS. Diss. 'ooi gm. in C 2 H 5 OH and dilute to 6 c.c. H 2 S0 4 (cone.) : no change. AgNOs : pale yellow flocculent ppt. of Ag meconate, sol in NH 4 OH. FeCl 3 : dusky purple colour ; boil : a ppt. of basic ferric meconate. CaCl 2 , stir with glass rod : white silky ppt. of Ca meconate. Pb2C 2 H 3 02 : pale } r ellow ppt., insol. in acetic acid but sol in dil. HNO 3 . CuS0 4 and one drop of NH 4 OH : green ppt. Uric Acid. C 5 ILN403 or (NH) 4 C 2 (CO) 3 . Colourless crystals only slightly sol. in aq. , insol. in alcohol and ether. Dissolves in KOH and NaOH, and in sols, of salts possessing an alkaline reaction. DRY TESTS. Heated in tube : does not melt, gives orFNH 3 , cyanic acid and HCy ; cyanuric acid (HCyO) 2 is left. Heated with NaOH : NH 3 and NaCy ; the residue gives Prussian blue with FeSO 4 . HN0 3 dissolves uric acid with effervescence, the sol. slowly evaporated to dryness on a W.B. and moistened with NH 4 OH yields a crimson colour (murexide) ; NaOH changes this to purple. H 2 S0 4 : sol., does not char when heated ; CO, CO 2 and SO 2 evolved. WET TESTS. Diss. -oi gm. of Na urate in i c.c. NaOH. HC1 : white ppt. of uric acid. Diss. *oi gm. uric acid in i c.c. of Na 2 CO 3 and place a drop on filter paper moistened with AgNO 3 : black stain of reduced Ag. Fehling's solution is reduced on warming. 54 HIPPURIC ACID Hippuric Acid. C 9 IL0 8 . Colourless prisms, bitter taste, acid reaction, slightly sol. in aq. DRY TEST. Heated with soda lime : NH 3 and benzene (C 6 H (i ) are evolved. WET TESTS. Diss. 'I gm. of hippuric acid in dil. NH 4 OH and boil off any excess of NH 4 OH. HC1 : white ppt. of hippuric acid. FeCls flesh-coloured ppt. Ag-NOs : white ppt. MKTHYL ALCOHOL AND ETHYL ALCOHOL 55 AL,COHOL,S AND THEIR DERIVATIVES. Methyl Alcohol (Wood Spirit). CILOH. Colourless volatile liquid with a ' ' spirituous ' ' odour. Neutral, boils 60, burns with non-luminous flame. Sp. gr. "7972. When mixed with aq., heat is evolved and the volume contracts. Use '5 c.c. for each test. H 2 S04 (cone.), warm : dimethyl ether, recognised by its odour. H 2 S0 4 and Na formate : characteristic odour of methyl formate. H..S0 4 and '01 gm. salicylic acid, warm : odour of oil of winter green (methyl salicylate). H.,S0 4 (i to i aq.) 5 c.c. and i gm. of K 2 Cr 2 7 and 5 c.c. methyl alcohol, distil from a test tube and test the distillate for formic acid. Ethyl Alcohol (Spirit of Wine). C 2 H5.0H. Colourless volatile liquid with characteristic odour and burning taste. Sp. gr. '7938 at 15*5 ; boils 78*4 C., and burns with a non-luminous flame. When mixed with aq., heat is evolved and the vol. contracts ; mixes with ether and carbon bisulphide in all proportions. Dissolves many salts, oils, resins, etc. Use '5 c.c. for each test. H 2 S0 4 (cone.), warm : ether and ethene (C 2 H 4 ) which burn with a luminous flame. Aldehyde test. Add K 2 Cr 2 7 and H 2 S0 4 , warm : odour of aldehyde (CH 3 .CHO) and the solution becomes green. Distil and test distillate for aldehyde by the rosaniline test. H 2 S0 4 (cone.), warm with strong alcohol and i gm. solid Na formate or Na acetate, or Na benzoate, etc., : the well-marked odour of formic, acetic, benzoic or other ether. lodoform test. Add '5 c.c. Na 2 C0 3 and sol. of iodine in KI, drop by drop, until the sol. retains a brown colour, warm to 60 C. ; on cooling, iodoform (CHI 8 ) separates in yellow six-rayed crystals ; the ppt. and sol. have a peculiar saffron-like odour. Aldehyde, acetone, acetic ether, etc. , also yield iodoform. 56 AMYL ALCOHOL AND ETHER KOH and CS 2 : yellow ppt. of pot. xanthate KC 2 H 5 COS 2 , to this add CuSO* and HC1 : a brown ppt. of copper xanthate, this becomes bright yellow and emits an offensive odour. Hg2N0 3 > boil : white ppt. of HgNO 3 , on adding NH 4 OH it becomes grey or black. (Distinction from methyl alcohol.) To detect methyl alcohol in ethyl alcohol. Add K 2 Cr 2 07 and H 2 S0 4 to oxidize them into formic and acetic acids ; allow to stand for some time ; distil, add a slight excess of Na 2 C0 3 to the dis- tillate and concentrate ; acidulate with acetic acid ; add AgNO 3 and warm, if much metallic Ag is reduced (due to formic acid) then methyl alcohol is present. Amyl Alcohol. Colourless, oily liquid, strong odour, causes coughing ; only slightly sol. in aq. ; boils 132 C. Use '5 c.c. for each test. H 2 S0 4 (cone.), warm : reddish brown colour, next add '5 c.c. glacial acetic acid and i c.c. FeCl 3 and warm again : a purple colour. Na acetate, about 'i gm. and 5 c.c. H 2 SO 4 , warm : odour of pears, due to the amyl acetate, intensified by pouring the mixture into water ; this applies to the following test also. K 2 Cr 2 7 about 'i gm. and 5 drops H 2 S0 4 , warm : odour of amyl valerate Ether (Ethyl Oxide). (C 2 IQ.O. Mobile, colourless liquid, with a characteristic pleasant ethereal odour and sweet taste; very -inflammable, burns with a luminous flame. (Alcohol burns with a non-luminous flame.) Mixtures of ether vapour and air explode violently on ignition. Sp. gr. 736 at o C., boils 34*6 C. Very volatile, when placed on the skin it produces a feeling of great coldness. Magenta (rosaniline acetate) is insol. in ether, if dry and free from alcohol. Mixes with absolute alcohol and CS 2 , but i part of ether requires 9 parts of aq. for its solution. Dissolves fats, oils, resins, india rubber, phosphorus, iodine, sulphur, etc., readily. 'Cl and Br act upon it readily. Na and K do not act upon it. FORMALDEHYDE, ACETAI7 and H 2 SO 4 green in the cold. Does not oxidize bright sodium. Does not turn brown with either strong KOH or strong H 2 SO 4 . GLYCEROI,, HYDROXYI, AND CARBON BISULPHIDE 59 Glycerol or Glycerin. C 3 H 5 (OH) 3 . A colourless, odourless, oil-like liquid, neutral, with sweet taste ; boils 290, and yields acrolein (C 2 H 3 .CHO) recognised by its disagreeable odour. Very hygroscopic, mixes with aq. and alcohol in all proportions ; almost insol. in chloroform and in ether. Marks paper like oil, but the stain is removed on soaking in aq. Use '5 c.c. for each test. Heated alone, or with HJSCh, KHS0 4 , or P 2 5 : the disagreeable odour of acrolein is evolved. NaOH, heat : no change. Borax bead moistened with glycerol and heated in the outer edge of the bunsen flame gives a momentary green colouration. Sulphur, boil : unpleasant odour of allyl mercaptan, etc. Phenol, H 2 S0 4 and glyeerol, each two drops, mix, heat to about 120 ; add water and excess of NH 4 OH : crimson colour. UNCLASSIFIED. Hydroxyl. ILCk Colourless liquid without odour; generally used as a 10 vol. sol. in water. Decomposed on warming (oxygen evolved) and by organic substances. TESTS. Use i c.c. for each test. Litmus sol. : Bleached. KMn0 4 sol. : Bleached. PbS : Converted into white PbSO 4 . KI and starch paste : blue colour from the liberation of iodine. Ether and KaCraO? sol., shake : evanescent blue colour. Carbon Bisulphide. CS 2 . Colourless, mobile, highly refractive liquid, odour usually offensive, but ethereal when pure. Sp. gr. 1-292. Very volatile, boils 46-6 C., its vapour is extremely inflammable (can be ignited by a test tube containing hot oil) ; yields SO 2 when burnt ; if with insufficient air, in a beaker 6*r tube, S is deposited. Almost insol. in aq., but readily sol. in alcohol and ether. It readily dissolves S, P, I, caoutchouc, oils and fats. Use '5 c.c. for each test. 60 UREA KOH, boil : brown sol. of K 2 CO 3 and K 2 CS 3 ; add one drop of Pb acetate : black PbS. H 2 S0 4 (cone.) on shaking : ppt. of S. KOH (in alcohol) shake : crystals of pot. xanthate. Urea (Carbamide) CO(NH 2 ) 2 . Crystallizes in four-sided prisms, deliquescent, very sol. in aq. and in alcohol, very slightly in ether. Melts 132 ; taste resembles saltpetre. DRY TKST. Heat '01 gm. in a dry tube : evolves NH 3 , etc., the residue contains cyanuric acid and biuret, a sublimate of biuret is also formed ; ex- tract the biuret with warm water, filter, add to filtrate a drop of dil. CuSO 4 and excess of NaOH : purple colour. Heated with NaOH or Na 2 C0 3 : NH 3 . WET TESTS. Diss *i gm. of urea in 7 c.c. aq. HN0 3 (free from HNO 2 ) : crystals of urea nitrate (only from strong sols.). H 2 C 2 4 (oxalic acid) : tabular prisms of the oxalate (only from strong sols.). Hg2N0 3 : a flocculent ppt. of CO(NH 2 ). 2 .2HgO, even in very dil. sols., sol. in NaCl, reprecipitated by further addition of Hg2NO 3 . KBrO (or KC10) : decomposes urea with effervescence into CO 2 , H 2 O and N. (KBrO can be made by adding cold KOH to Br aq. until decolourized.) HN0 2 (nitrous acid) or a sol. of KN0 2 and dil. HgSO* (or HC 2 H 3 O 2 ) decom- poses urea into N and CO a . CARBOHYDRATES. SUGARS, AMYLOIDS AND CEU^ULOSE. Glucoses. DKXTROSK (Grape Sugar), C 6 Hi2O 6 ,H 2 O. Crystallized, colourless, and without odour ; less sweet than cane sugar. The crystallized sugar melts at 80 to 86 ; the anhydrous at 146. Sol. in aq. and in dil. alcohol, insol. in ether. Dextrorotatory, [#] D = + 52*5; readily ferments with yeast. Its osazone melts at 206. DRY TESTS. Heated : turns brown and evolves odour of caramel. EUSO^ (cone.) : no change ; warm : dark brown colour. (See sucrose.) WET TESTS. Diss. o'i gm. in 6 c.c. aq. KOH (strong), warm : brown solution ; on adding HNO 3 changes to yellow and the odour of caramel is evolved. (Compare with cane sugar.) Pb acetate, boil, add NH 4 OH until a white ppt. just forms, boil : the ppt. becomes pink colour. (Cane and milk sugars do not give this reaction.) Cu acetate and two drops of acetic acid, warm : ppt. of red Cu 2 O. (See milk sugar.) AgNOs and NH 4 OH, place the test tube in a beaker of boiling water : a silver mirror forms on the test tube. Fehling's solution : reduced immediately on warming. KOH and 3 drops of picric acid sol., boil : the yellow colour changes slowly to red (picramic acid), CH 2 .OH.NH 2 .(NO 2 ),. (Fruit Sugar), CcH^O,,. Is distinguished from dextrose by its rotating the polarised ray to .the left, [rt] D = - 1 13*9 ; by being more sol. in aq. and in alcohol, and by yielding a ppt. with Ca(OH) 2 . Saccharoses. SUCROSE (Cane Sugar). Crystallized in colourless oblique prisms ; readily sol. in aq., but sparingly sol. in alcohol. Melts at 160, when cold is vitreous, i.e., non-crystallized (barley sugar). Dextrorotatory, [tf] D = + 66 '5. Cane sugar does not form an osazone. DRY TEST. Heated to about 200 it changes to caramel (brown), then chars, evolves gases and a characteristic odour. 61 62 SACCHAROSES H 2 S0 4 (cone.), chars sugar and syrup. WET TESTS. Diss. o'i gm. in 5 c.c. aq. KOH (strong), heat, does not become brown, nor is the odour of caramel emitted on acidifying with HNO 3 . (See glucose.) Cu acetate alone, or when warmed with acetic acid, is not reduced. (See glucoses.) AgN0 3 and NH 4 OH, warm : no silver mirror. Pb acetate and NH 4 OH, boil, the white ppt. does not become yellow. Fehling's solution is not reduced (by a fresh sol. of sugar) ; if, however, the sugar be previously "inverted" by warming with 2 drops of HC1 or H. 2 SO 4 , Fehling's solution is quickly reduced on warming. lyACTQSE (Milk Sugar). C, 2 H 22 O n ,H 2 O. Crystallizes in prisms, gritty and not so sweet as cane sugar; sol. in aq., insol. in ether and absolute alcohol. Dextrorotatory, [tf] D = + 52*53. Its osazone melts at 200 ; does not ferment with yeast. DRY TESTS. Heated, becomes brown. H 2 S0 4 (cone.), warm : blackens or chars, but less readily than cane sugar. WET TESTS. Diss. -i gm. in 6 c.c. aq. KOH, boil : brown colour, discharged on adding dil. HNO 3 , and odour of caramel evolved. Cu acetate (and 2 drops of acetic acid) on boiling and standing is not reduced unless the solution be concentrated. AgNOa and NH 4 OH : Ag mirror when warmed. Pb acetate, boil and add just sufficient NH 4 OH to produce a ppt., again boil, the white ppt. becomes pale yellow ; the ppt. from cane sugar remains white and that from glucose becomes pink. KOH and picric acid, boil : red (picramic acid). Fehling's solution, warm : red ppt. of Cu 2 O. MAI/TOSE. Ci 2 H 22 On,H 2 O. Crystallized, very sol. in aq., almost insol. in absolute alcohol; readily fermented. Dextrorotatory, [] D = + 140*6. Its osazone melts 206. DRY TEST. Moisten the powder, add cone. H 2 SO 4 : clear sol., chars on warming. WET TESTS. Diss. *i gm. in 5 c.c. aq. NaOH, boil : yellow, then brown colour, dil. HNO 3 discharges the colour and the odour of caramel is evolved. Fehling's solution, boil : red ppt. of Cu 2 O. Cu acetate, and 2 drops of acetic acid, is not reduced on boiling. Pb2C 2 H 3 2 and NH 4 OH : white ppt., which becomes pink on boiling. (See glucose.) SACCHAROSES. Picric acid and NaOH : red picramic acid (C 6 H 2 ,NH 2 (NO 2 ) 2 OH). cose and lactose also give this reaction. 63 Glu- GENERAI, REACTION. (a) When a molecule of a sugar containing an aldehyde (CHO) or a ketone group (CO) is acted upon by phenyl hydrazine it yields a hydrazone. j CH 2 (OH)(CH.OH) 4 CHO + ( C 6 H 6 NH.NH 8 = I Glucose ( Phenyl hydrazine H 2 + ( C 6 H 5 NH.N:HC(CH.OH) 4 (OH)CH 2 I Glucose phenylhydrazone (b) When an "excess" of phenylhydrazine is added the CH(OH) group next the end is oxidized to CO, and part of the phenyl hydrazine is reduced to aniline and NH 3 , and the oxidation product of the phenyl hydra- zone combines with a second molecule of phenyl hydrazine and yields an osazone. CH,.(OH)(CH.OH) 3 CO.CH:N.NH.C 6 H 5 + ( C 6 H 5 NH.NH 2 = ( Phenyl hydrazine CH 2 (OH)(CH.OH) 3 C(N.NHC G H 5 )CH:N.NH.C 6 H 5 + H 2 O Osazone KXPT. Diss. '5 gm. of a sugar in 5 c.c. aq., add 3 c.c. phenyl hydra- zine and 3 c.c. acetic acid, place the test tube in boiling water for about ten minutes, when the osazone comes down as yellow crystals. To identify the sugar, filter off the osazone, wash, dry and determine its melting point or examine its decomposition products. SUMMARY OF SUGAR REACTIONS. TEST. GLUCOSE. SUCROSE. ivACTOSE. MAI/TOSE. Rotation []D= + 52-5. []=+ 66'5. []D= + 52-53 . []D - + I40'6. Heated alone Browns and yields Yields barley su- Browns. caramel. gar and caramel. H 2 SO 4 (cone.) No change, chars Chars in the cold. Chars on heating. Chars on heating. on warming. NaOH sol., heated Becomes brown ; No change. Becomes brown ; Becomes brown ; add HNO ;} = car- add HNO = car- add HNO 3 = car- amel odour. mel odour. amel odour. Pb. acetate and Pink ppt. White ppt. Yellow ppt. Pink coloured ppt. NH 4 OH Cu acetate and Cu 2 O on boiling. No change. No change. No change. acetic acid Fehling's sol. Cu 2 O on boiling. No change. Cu 2 O on boiling. Cu 2 O on boiling Pheuyl hydrazine Yellow crystals of No osazone. Yellow crystals, Yellow crystals of glucosazone, m.p. Ivactosazone. Maltosazone 206. m.p. 200. m.p. 206. 64 AMYLOIDS Amyloids. (CoHio0 5 )n STARCH. White powder, with peculiar harsh feel when rubbed between the ringers. Under the microscope the grains of many varieties of starch are seen to be made up of concentric layers, and to show a well-marked cross with Nicol's prisms. Insol.in cold aq. ; in hot aq. the granules burst and yield a translucent fluid, strong sols, set to a jelly : "starch paste " DRY TESTS. When heated (to 150 C.) it is changed into dextrin (or British gum) which is sol. in aq. , and gives a reddish colour with tincture of iodine, instead of blue. At higher temps, it chars and emits an unpleasant odour. WET TKSTS. Grind *oi gm. starch with i c.c. of cold aq., make up to 5 c.c. with aq. and boil. Iodine (tincture) : a blue colour, which disappears on boiling, but returns when cold, if not boiled too long. Reducing substances, e.g., Na 2 SO 3 , Na,S 2 O 3 , and SH 2 prevent the formation of the blue colour ; if such are present, add 3 drops of K* burns with smoky flame. Slightly sol. in cold aq., readily sol. in alcohol, ether and chloroform. Yields crystallized salts with acids. KOH and NaOH (but not NH 4 OH) decompose the salts and set free the aniline. WET TESTS. Use i drop of aniline from the end of a glass rod for each test. H 2 S0 4 (cone,) : solution, on long boiling becomes brown ; stir a dil. sol. of K 2 Cr 2 OT (in test tube, watch-glass or porcelain basin) with a glass rod dipped into the above solution : blue colour. The following tests apply to both the base and its salts. NaOH in alcohol and 2 drops of chloroform, warm : nauseous odour of carbylamine (phenol isocyanide). NaOCl, or bleaching powder solution : purple colour. Then add dil. NH 4 SH : magenta colour, fleeting. KClOs (dil.) to dil. aniline sol., i drop to 5 c.c. aq., then run a little cone. H 2 SO 4 carefully down the side of the tube : a violet colour rikg at the junction of the liquids. Bromine water : pinkish ppt. of tri-bromaniline (C6H 2 .Br 3 NH. 2 ). Diazo reaction. Add 5 drops of KNO 2 to a sol. of aniline in dil. HC1 cool the test tube under the tap, next add a few drops of a or ft naphthol in NaOH : the scarlet colour of benz-azo-naphthol (C 6 H 5 N:N.C 10 H 6 OH). Pyridine. C 5 H 5 N. Colourless oily liquid, with strong characteristic odour. Obtained from bone oil and the distillatibn of alkaloids. Fumes with volatile acids ; darkens on exposure. Boils 116; sol. in aq., alcohol and ether. A strong base, precipitates Fe(OH) 3 , A1(OH) 3 etc., from their salts. Yields salts with acids, from which NaOH and KOH set free the pyridine. WET TESTS. Use i drop of pyridine for each test. H 2 S0 4 (cone.) : white ppt., dissolves in excess to a colourless sol. Br aq. in excess added to the HC1 sol. of pyridine : yellow ppt. (C 6 H 5 NBr 2 ). H 2 PtCl 6 and HC1, boil and cool : orange-yellow ppt. of (C s H 5 N) 2 .H 2 PtCl (i . 68 QUINOUNE 69 Quinoline. C 9 H7N. Colourless, limpid liquid, obtained from bone oil and coal tar; with peculiar, somewhat aromatic odour, becomes brown on exposure. Boils 238. Its vapour burns with a luminous, smoky flame. Sparingly sol. in aq., but readily in many organic liquids. A strong base, yields deliquescent salts. It precipitates Fe(OH) 3 , A1(OH) 3 , etc., from their salts. WET TESTS. Use i drop for each test. H 2 S0 4 (cone.) : crystals of sulphate, soluble in excess. H 2 PtCl 6 to the HC1 sol. : yellow ppt. of (C 9 H 7 N). 2 H 2 PtCl 6 ; sol. in warm aq. AgN0 3 on shaking : white ppt. which dissolves on warming, but re-forms on cooling ; on long boiling some silver is reduced. K 2 Cr 2 7 and 3 drops of HC1 : ppt. of yellow crystals of dichromate, (CyH 7 N). 2 H 2 Cr. 2 O 7 , dissolves on warming. (Distinction from pyridine.) ALKALOIDS. PRECIPITANTS. The alkalis and alkali carbonates precipitate many of the alkaloids from strong sols, of their salts. Platinum Chloride (Chloroplatinie aeid), H 2 PtClo, forms with the hydro- chlorides of the alkaloids, salts similar to (NH 4 ) 2 PtCl c in which the NH 4 is replaced by the alkaloid ; these salts, when soluble, are most readily formed by evaporating H 2 PtCl c with the hydrochloride of the alkaloid over a water-bath ; extract the residue with alcohol. Solution of Iodine in KI (deci-normal sol.) precipitates the alkaloids as yellow or brown polyiodides ; to convert these into sulphates evaporate the well- washed ppt. to dry ness with H 2 SO 4 over a W.B. Sols, of HgI 2 in KI, of CdI 2 in KI, and of BiI 3 in KI also yield ppts. with the alkaloids. ' Tannie aeid : white, yellowish or brownish ppts. ; the alkaloid can be obtained from these in the free state by adding KOH and taking up with ether, amyl alcohol, benzene, etc. Phospho-molybdie aeid. Gives yellow ppts. with alkaloids. To prepare it boil Am. motybdate with Na 2 HPO 4 , well wash the ppt., diss. in warm Na 2 CO 8 , evaporate to dryness, ignite ; if reduction takes place (add HNO 3 and re-ignite) warm with water and dissolve in a large excess of HNO 3 . Picric acid. Gives yellow ppts. with most alkaloids. DIRECTIONS FOR APPLYING THE TESTS. COLOUR TESTS. Perform the colour tests on a glass plate over white paper, or on a white porcelain slab ; those requiring heat should be done on watch-glasses, porcelain crucible lids, or clean pieces of broken dishes. Use i drop of the reagent and a small quantity of the alkaloid, about '2 mgm., or a quantity not larger than the size of a pin's head, for each test, unless other- wise directed ; for liquids use i drop from the end of a thin glass rod about Y% inch thick. Bring the reagent and substance into contact with a pointed glass rod. 70 CONIINE, NICOTINE, ATROPINE AND DATURINE 7 1 VOLATILE LIQUID ALKALOIDS. Coniine. CsHnN. (Propyl Piperidine). Colourless oily liquid, becomes brown on exposure, with offensive mouse-like odour, sol. in water, alcohol, etc. ; distils in steam ; a strong base. Dissolve i drop in 5 drops of water. COLOUR TESTS. HJS0 4 : colourless sol., blackens on heating. H 2 S0 4 and K^Cr^O? : green colour. WET TEST. Alcohol, add 2 drops to i drop of a solution of coniine, in an evaporating dish, then 2. drops CS.., let stand 3 minutes, add one drop of dil. CuSO 4 : a brown colour. (Distinction from nicotine.) Nicotine. Colourless volatile liquid, with strong characteristic odour, turns brown on exposure. Boils at 250 with decomposition, readily distilled in steam. Readily sol. in aq,, alcohol and ether. TESTS. The odour is one of the best tests. Formaldehyde, mix 2 drops of formalin with 2 drops of a 10 per cent, sol. of nicotine on porcelain, then add 2 drops of HNO 3 : pink colour. (Distinction from Coniine.) NON-VOLATILE SOLID ALKALOIDS. (Arranged in alphabetical order.) Atropine and Daturine (Isomers). COLOUR TESTS. Divide i mgm. into 3 parts. H-jS04 : colourless sol., brown on warming. A pleasant odour of flowers when heated with H 2 SO 4 or H 2 CrO 4 . HNO& (fuming) : solution, evaporate to dryness over W.B., and add i drop of alcoholic KOH to the colourless residue : violet, and then cherry-red colour. Ba water, evaporate and heat strongly : odour of hawthorn blossom. 72 BRUCINE AND CAFFEINE Brucine. C23H 26 N 2 4 4H 2 0. Colourless, right rhombic prisms or needles. Sparingly sol. in cold aq., readily sol. in alcohol, amyl alcohol, chloroform, but less in benzene ; nearly insol. in ether. Its salts are readily sol. in water. Brucine and its salts are very bitter and poisonous. When carefully heated it loses water and sublimes unchanged. COLOUR TESTS. Divide i mgm. of brucine nitrate into 7 parts. H 2 S0 4 (cone.) : a pale rose tint becoming yellow, and a fleeting red if a trace of HNO 3 be added (characteristic). H 2 S0 4 and solid K 2 Cr 2 07 : red-brown colour. HNOs (cone.) : a deep red colour, yellow on warming ; drive off the free HNO 3 over a water bath and add a drop of SnCL. : a deep purple colour. Cl water : a fleeting pink or red colour, turning to a yellowish brown on addition of NH 4 OH. Erdmann's reagent (see index) : pale red changing to yellow or orange. Mandelin's reagent (see index) : rose colour, rapidly changing to orange. Hg(NO>2 (f ree from acid) : colourless sol., warmed on a water bath : car- mine. (Distinction from strychnine.) PRECIPITANTS. Diss. i mgm. of brucine nitrate in 3 c.c. of aq. The alkalis and their carbonates precipitate brucine from its salts. NH 4 OH : ppt. sol. in excess, but it slowly crystallizes out on standing. KCNS : white ppt. sol. in excess. Caffeine (Theine). C 8 HioN 4 2 . Silky needles, bitter taste; sol. in alcohol and ether. Melts 232. Sublimes unchanged ; a weak base. DRY TEST. Soda lime, heat : NH 3 evolved ; carbonate and cyanide left ; test for cyanide by HC1 and Fe salts. COLOUR TESTS. Divide i mgm. into 4 parts. H. 2 S0 4 (cone.), and dry K 2 Cr 2 7 : a green colour slowly appears. HNO :i , evaporate to dry ness : a yellow-red stain ; cool and add NH 4 OH : purple (murexide). Br water, dry on W.B. : yellow to crimson residue, add NH 4 OH : purple (murexide). Mayer's reagent (see index), no change. (Distinction from other alkaloids.) WET TEST. NaOH, boil : fish-like odour of methylamine. CINCHONINK, COCAINE AND CODEINE. 73 Cinchonine. CiglLzNCk Crystallizes in lustrous prisms. Sparingly sol. in aq., more sol. in alcohol, atnyl alcohol, ether and chloroform. Bitter taste. Melts 255 to a colourless fluid. DRY TEST. If cautiously heated in a dry tube it sublimes unchanged. COLOUR TESTS. Divide i mgm. into 3 parts. H 2 S0 4 (cone.) : colourless sol. ; warm : brown to black. HC1, and evaporate to dry ness : purple colour and purple vapours, the same as quinine and quinidine. Mandelin's reagent : same as quinine and quinidine. PRECIPITANTS. Diss. i mgm. cinchonine sulphate in 3 c.c. aq. This sol. is not fluorescent. NaOH, KOH, NH 4 OH and their carbonates : precipitates of amorphous cinchonine from its salts. Cl water, 5 drops, and 5 drops NH 4 OH : yellowish ppt. K 4 FeCy 6 : flocculent ppt. of cinchonine ferrocyanide, sol. in excess of K 4 FeCy 6 on warming , on cooling it crystallizes out in brilliant yellow scales or needles. Cocaine (Methyl-benzoyl-ecgonine). Colourless prisms. Melts 98 ; sublimes at higher temps. Readily sol. in alcohol, ether, chloroform, benzene, and petroleum ; sparingly in water. Its salts are readily sol. in water. COLOUR TESTS. Divide i mgm. of cocaine hydrochloride into 3 parts. H 2 S0 4 : no colour, add a particle of K 2 Cr. 2 O7 : brown colour. KMn0 4 (strong sol.), add to alcohol sol. in watch-glass : purple ppt. of cocaine permanganate. K 2 Cr 2 7 and 2 drops HC1, on watch-glass : light yellow ppt. (charac- teristic). WET TESTS. Diss. i mgm. cocaine hydrochloride in 2. c.c. aq. H 2 S0 4 (cone.), warm : odour of benzoic acid ; add 2 c.c. alcohol, boil : odour of ethyl benzoate. FeCls, one drop, boil : red-brown colour. Codeine (Methyl morphine) Ci7Hi 7 NO(OCH 3 )OH. Crystallizes in orthorhombic prisms. Melts at 150. Moderately sol. in hot aq. ; readily sol. in alcohol, atnyl alcohol, ether, chloroform and benzene. Alkaline reaction. 74 MORPHINE AND NARCOTINE COLOUR TESTS. Divide i mgm. into 5 parts. H 2 S0 4 : colourless sol. ; blue when warmed ; (a) add FeCl 3 to cold sol. deep blue ; (b) grind with sugar : purple-red on standing. HN0.5 : a yellow colour. Froehde's reagent : green and finally blue sol. Cl water : dissolves ; add NH 4 OH : orange. Moisten with formalin, add 2 drops cone. H. 2 SO 4 : violet colour. Morphine. Cn Crystallizes in colourless prisms, sol. in alcohol and amyl alcohol, almost insol. in cold aq., ether, chloroform and benzene ; sparingly sol. in hot aq., poisonous. COLOUR TESTS. Divide i mgm. of morphine hydrochloride into 8 parts. H-.SOi : pale rose colour ; warm : violet and then brown, add a trace of HNO 3 and warm : red colour. H 2 S0 4 and a particle of KaCr^O? : dull green colour. H 2 S0 4 (cone.) 2 drops, and a fragment of FeSO 4 , warm on a W.B. for one minute, stir, cool, add excess of NH 4 OH : pink, then red and violet. (Distinction from codeine.) Formalin, i drop, and 2 drops cone. H. 2 SO 4 : deep purple colour. HNO.j : bright orange colour. FeCl* (neutral) : an indigo blue colour with strong sols, of morphine salts. Froehde's reagent : violet, changing to green. lodie acid, one drop : free iodine. PRECIPITANTS. Diss. i mgm. of morphine hydrochloride in 2 c.c. aq. NaOH, KOH, NH 4 OH and their carbonates : ppt. of morphine, readily sol. in an excess. Narcotine. Cs Colourless lustrous prisms or needles. A weak base. COLOUR TESTS. Divide i mgm. into 4 parts. H 2 S0 4 (cone.) : yellow solution changing to red and dusky violet when warmed slowly on a water bath. FeCl 3 restores the red colour. H 2 S0 4 (cone), and dry K 2 Cr 2 7 : rich brown colour. HN0 3 : yellow solution, orange on warming. Froehde's solution : green sol. ; warm : red. PAPAVERINK AND QUININE 75 PRECIPITANTS. Diss. i rngm. narcotine in 2 c.c. dil. HC1. Cl water : greenish yellow ; add NH 4 OH : orange (only from strong sols.). Br water added drop by drop to the HC1 sol. : yellow ppt. ; boiled : red colour. Destroyed by slight excess of Br. Papaverine. Crystallized in prisms, feebly alkaline, not poisonous, soluble in hot alcohol, crystallizes on cooling ; insol. in water. COLOUR TESTS. Divide i mgm. into 3 parts. H 2 S04 : colourless or yellow solution becoming violet on warming. Froehde's reagent : green through blue to violet colour, and cherry red. Cl water and NH 4 OH : red-brown colour, turning to very dark brown. Iodine solution (with strong sol.) : dark red, then brick-red and dark red again. Quinine. C 2 <,H 2 4N 2 2 ,3H 2 0. Crystallized; slightly sol. in cold aq., more soluble in hot water and NH 4 OH, in alcohol, chloroform, ether, petroleum, and benzene. Bitter taste ; turns litmus blue. Solutions of quinine salts, especially of the sulphate and other oxidized acids, exhibit a strongly marked blue fluorescence. COLOUR TESTS. Divide i mgm of quinine sulphate into 3 parts. H 2 S0 4 (cone.) : colourless solution, add particle of K 2 Cr 2 O 7 : grass green. HC1 (cone.) evaporate to dryness in porcelain dish : a violet colour just before it chars, and violet vapours, like iodine, are evolved. Mandelin's reagent : no change : add one drop HNO 3 : violet. PRECIPITANTS. Diss. i mgm. quinine sulphate in 2 c.c. aq. Ammonia, alkalis, and their carbonates : ppt. of amorphous quinine from strong sols., which gradually becomes crystalline. Cl water and an excess of NH 4 OH : a green colour. Add 3 drops of esh K 3 FeCy fi sol. to this : bright red. 76 STRYCHNINE AND VERATRINE Strychnine. CaiH^NaCk Strychnine and all its salts are virulent poisons. Crystallizes in white rhombic prisms. Readily soluble in hot chloroform ; very sparingly sol. in hot water (i in 2500), benzene, amyl alcohol, absolute alcohol and ether ; slightly sol. in dil. alcohol. Its salts are sol. in aq. and in alcohol, but insol. in ether, chloroform, amyl alcohol and benzene ; all have a bitter taste, i part in 700,000 of aq. can thus be recognised. COLOUR TESTS. Divide i mgm. of strychnine sulphate into 3 equal parts. H 2 S0 4 (cone.), and a fragment of either K 2 Cr 2 7 , Mn0 2 , Pb0 2 , or K 3 FeCy fi : beautiful purple colour changing to red and green. NOTE. This test does not answer with St. nitrate, nor with the sulphate in the presence of antipyrine. Strychnine is often added to anti- pyrine for medicinal purposes. HN0 3 (cone.) : colourless sol., yellow when warmed. Mandelin's reagent : blue colour changing to violet ; NH 4 OH changes it to rose colour. Characteristic. PRECIPITANTS. Diss. i mgm. of strychnine sulphate in 4 c.c. aq. KOH and NaOH and their carbonates give with St. salts, white crystalline ppts. The ppt. with NH 4 OH is sol. in an excess, but gradually crystallizes out in needles. Cl water : white ppt., sol. in excess. Iodine (strong sol. in KI) : reddish brown ppt. KCNS : a white ppt. insol. in excess ; slowly formed in dil. sols. Veratrine. Amorphous, white or grey, crystallizes from alcohol, No odour, but causes violent sneezing. Sol. in CHC1 8 and alcohol, sparingly in ether and amyl alcohol. COLOUR TESTS. Divide i mgm. into 7 equal parts. H 2 S04 : yellow solution, red when heated. HN0 3 : pale yellow to green. HC1 (cone.) : colourless sol. ; boil : red colour. Erdmann's reagent : yellow to deep red. Mandelin's reagent : dusky yellow to crimson. Froehde's reagent : yellow, becoming cherry-red on standing. When rubbed with 3 times as much cane sugar and H 2 SO 4 (2 drops) it becomes yellow (green by reflected light) and finally indigo blue. ACETANILIDE, ANTIPYRINE AND PHENACETIN 77 ARTIFICIAL ALKALOIDS. Acetanilide (Antifebrin). CsIL.NH.COCIL. Crystallizes in colourless lustrous plates. Melts 113. Readily soluble in alcohol, ether, chloroform and boiling aq. COLOUR TESTS. H 2 S0 4 (cone.), stir with a little powdered K 2 Cr 2 O7 : red streaks, quickly turning green. Mandelin's reagent : orange red ; this becomes red and then grey. Hg2N0 3 , 2 drops, on slow evaporation : green residue ; stir this with a little cone. H 2 SO 4 : deep red. WET TESTS. Diss 'i mgm. in 3 c.c. of alcohol. FeCl 3 , boil, becomes turbid and darker in colour. (See antipyrine and phenacetin.) KOH, warm : K acetate and aniline. Test for the aniline by warming with 2 drops of CHC1 3 : odour of carbylamine ; or dilute with aq., shake up with ether, separate the ethereal sol. and test it for aniline ; test the water sol. for acetic acid. H 2 S0 4 (cone), and alcohol, warm : odour of ethyl acetate. Antipyrine (Phenazone). Cn Colourless, odourless crystals. Melts 114. Bitter taste, neutral re- action, yields salts. Soluble in water and in alcohol, sparingly in ether. DRY TEST. Heated in a dry tube : melts and chars, a brown liquid condenses. COLOUR TESTS. Divide i mgm. into 6 parts. H 2 S0 4 (cone.), warm : colourless. HNO.s (cone.), warm : yellow to red colour. HgCl 2 : white ppt. , dissolves on warming ; re-formed on cooling. KN0 2 , fragment, and 2 drops dil. H 2 S0 4 : bright reddish-yellow colour (isonitroso-antipyrine). Strong sols, of antipyrine yield green crystals. Mandelin's reagent : pale blue colour, evanescent. FeCl 3 , warm : deep red colour. Phenacetin (para-acetamido-ethoxybenzene). C 2 H 5 O.C6H4.NH.COCH3. Colourless, odourless, crystalline scales. Melts 135. Almost insol. in cold aq., fairly sol. in hot water and readily sol. in ether and chloroform. 78 DETECTION OF SINGLE ALKALOIDS DRY TESTS. Heat in a dry tube : melts and sublimes. Mix with twice its bulk of zinc dust or filings, and heat to charring; cool, boil with a little water, filter, add FeCl 3 : violet colour, due to the salicylic acid formed. COLOUR TESTS. Use i mgm. divided into 2 parts. HN0 3 (i to i aq.) warm-: orange colour, and yellow crystals on cooling. Add KOH in excess : red colour, which deepens on boiling. KN0 2 , grind with an equal bulk of phenacetin, mix with 2 drops cone. H 2 SO 4 and warm on a water-bath : green colour. WET TESTS. Diss. i mgm. in 2 c.c. aq. FeCl 3 (dil. sol.) warm : red colour. H 2 S0 4 (cone.) and alcohol, warm : odour of ethyl acetate. DETECTION OF SINGLE ALKALOIDS. 1. Heated on Pt foil : nitrogenous odour and smoky flame. 2. Heated with soda-lime : odour of NH 3 . 3. Placed on litmus paper and moistened with alcohol, a blue colour : a free alkaloid. The solution of the salt of the alkaloid must not be too dilute, and must be free from substances which would interfere with the tests. GROUP I. ATROPINE, (ANILINE).. CONIINE, NICOTINE AND MORPHINE. Add KOH to the sol. until it is just alkaline ; stir briskly and allow to stand. a. No ppt. ; (i). Heat with H 2 SO 4 or H 2 CrO 4 ; a characteristic pleasant odour of flowers. (2) Iodine is not separated on addition of HIO 3 : atropine. b. A disagreeable odour is evolved and oily drops separate : (aniline), nicotine, eoniine. Extract with ether and evaporate the ethereal extract to dryness with HC1: An amorphous residue : nicotine hydroehloride. A crystalline residue ; when boiled with HNO 3 becomes red, violet, green, blue, and finally brown, especially if free acid be present : eoniine. c. A ppt. sol. in excess : morphine or atropine. Confirm. Add iodie acid, Iodine is not separated : atropine. DETECTION OF SINGLE ALKALOIDS 79 Iodine separates out : morphine. FeCls neutral (dil.) : a blue or green colour, if the sol. be concentrated and neutral : morphine. GROUP II. ClNCHONINE, NARCOTINE AND QUININE. Add 2 drops dil. H 2 S04 and just neutralise with a saturated solution of NaHCO 3 , stir well and allow to stand 30 minutes. A precipitate : einehonine, nareotine or quinine. Heat cautiously : fuses and yields a sublimate of white needles : einehonine. NHiOH in excess, and shake with ether, (a) the ppt. does not dissolve : einehonine ; (b) it dissolves : nareotine or quinine. K 4 FeCy 6 to a neutral sol. : a white ppt. sol. in excess ; warm, bright yellow crystals separate out on cooling : einehonine. Cl water and 2 drops of NH 4 OH, (a) a deep red solution : nareotine ; (b) a green or blue sol. : quinine. GROUP III. BRUCINE, CAFFEINE, COCAINE, CODEINE, DIGITALIN, PAPAVERINE, PICROTOXIN, QUININE, SAUCIN, STRYCHNINE, VERATRINE. If the substance be liquid, evaporate to dryness on a watch-glass and stir the residue with a glass rod dipped in cone. H.>SO 4 . a. A rose colour becoming intensely red on addition of HNO 3 : brueine. Confirm (i) Cl water (the gas is better) : red. NH 4 OH changes this to yellowish brown ; (2) HNO 3 gives blood red, then yellow, changed to violet on addition of SnCL. b. A yellowish colour, becoming orange red and finally crimson on heating : veratrine. Confirm. Mix with 3 times its bulk of cane sugar and moisten with strong H 2 SO 4 : reddish brown, gradually turning to blue. c. Colourless or faint yellow on standing- : caffeine, cocaine, codeine, papaverine, quinine and strychnine. Confirm for caffeine. HNO 3 , dry on W.B., add NH 4 OH : purple colour (murexide). Confirm for cocaine. K. 2 Cr. 2 O 7 and 2. drops of HC1 : light yellow ppt. Confirm for codeine. H 2 SO 4 and FeCl 3 : deep blue colour. Confirm for papaverine. Iodine solution : dark red. Confirm for quinine. (i). Fluorescence in solutions of its salts; (2) Cl water and then NH 4 OH : green. Confirm for strychnine. (i) KCNS : white crystalline ppt. ; (2} a bitter taste in very dil. solutions ; (3) cone. H 2 SO 4 and solid K. 2 Cr. 2 O 7 : deep blue colour changing to wine red. d. A reddish-brown colour. 80 DETECTION OF SINGLE ALKALOIDS BP water, the reddish-brown colour changes to purple : digitalin. Confirm. Warm the solution in water with phospho-molybdic acid : bright green, which changes to blue on adding NH 4 OH : digitalin. e. A saffron colour, add K 2 Cr 2 7 (powder) a violet or brown colour changing to blue : pierotoxin. Confirm. (i) Moisten the substance with HNO 3 , dry on water bath and stir with a rod dipped in H. 2 SO 4 , then mix with excess of KOH : orange colour ; (2) add Fehling's solution, warm, ppt. of Cu. 2 O : pierotoxin. f. A blood-red colour : saliein. Confirm. (i) FeCl 3 : a pale brown, colourless on boiling and a dull yellow ppt. ; (2) AgNO 3 , warm, add excess of NH 4 OH and NaOH, a mirror of reduced Ag : saliein. NOTE. Digitalin, Pierotoxin and Saliein are not alkaloids, but resemble them physiologically. TABLES FOR QUALITATIVE CHEMICAL ANALYSIS. PRELIMINARY EXAMINATION. LIQUIDS. If the substance be a liquid, examine its reaction with litmus paper : It is neutral. Free acids, acid salts and the majority of the normal salts of the heavy metals must be absent. It is acid. Either free acids, acid salts or normal salts having an acid reaction, may be present. It is alkaline. Salts possessing an alkaline reaction, free alkalis, alka- line earths or their borates, carbonates, cyanides, silicates, phosphates or sulphides may be present. Evaporate a portion of the liquid in a watch-glass or on a piece of platinum foil. If it does not leave a residue the liquid may be water only ; if a residue be left, evaporate a larger quantity in a porcelain dish. The residue should be examined and described as to colour, crystalline form, etc., and then submitted to the preliminary tests as laid down for solids. SOLIDS. Examine the substance carefully for traces of crystalline form or structure, .note down the colour, lustre, degree of transparency, hardness, density, i.e., whether it has a light or heavy feel ; the odour, if any ; also the feel when rubbed between the fingers ; and ascertain whether it is attracted by a magnet. PRELIMINARY TESTS. The substance must first be ground down to the finest powder possible, unless it be already in that state. When several substances are present together in a mixture, the results obtained may not be exactly as they are here stated, since one reaction often masks or obscures another. Experiment J. Heat some of the powder in an ignition tube, i.e., in a piece of hard glass tubing about 2 inches long by ^ inch wide, and closed at one end. 81 82 TABLES FOR QUALITATIVE CHEMICAL ANALYSIS Inferences. 1. The substance does not change. 2. It decrepitates. 3. It changes colour without fusing. Cold. I Hot. Absence of organic mat- ter, moisture, combined water and salts of NH 4 , Hg, As, etc. Presence of nitrates, chlor- ates, sodium chloride, etc. White. Yellow. ZnO. White or yellow. Yellowish brown. SnO,, TiO 2 . Red-brown. Dark red. Fe,0 3 . Red. Black ; Hg globules HgO. 4. It changes colour and fuses. Yellow. Yellow or red-brown PbO. White or yellow. Orange or brown. Bi 2 O 8 . Yellow. Dark red. K,CrO 4 . Red. Black. Pb ; A. 5. The substance chars and evolves empyreu- matie odours and decomposition products. Chars readily, smell of burnt feathers. A smell of burnt sugar (caramel) is given off, afterwards becoming pungent. Chars slightly, acetone is evolved. The residue contains a soluble alkaline carbonate. The residual carbonate is insoluble in water. 6. It does not change colour. 7. Fumes are evolved and a sublimate is formed. (a) It sublimes without fusing. The sublimate is white. The sublimate is yellow when hot, white when cold. Presence of organic matter. Urates, alkaloids and pro- teids. From sugar, tartrates, cit- rates, malates, tannates, gallates, etc. From acetates. Organic compounds of NaOH, KOH, etc. Organic salts of the alkaline earths, etc. ' Most salts of the alkalis, certain salts of the alka- line earths, as chlorides and nitrates. Compounds of NH 4 , Hg, As, Sb, also S, I, SnCl, and CdCl,. PbCL sub- lin^es at a high tempera- ture. Oxalic, benzoic and succinic acids. NH 4 salts. Hg 2 Cl,. TABLES FOR QUALITATIVE CHEMICAL ANALYSIS Results. Inference A sublimate of white octahedral crystals. White quadrilateral prisms. (b) The substance fuses and yields a tvhite sublimate. Melts readily and evolves heavy fumes ; white crystalline sublimate. Fuses, changes to yellow ; at a red heat : sublimate of white acicular crystals. At a high temperature : a dark yellow fluid sublimate Bright scales sublime ; fuses to a reddish- yellow liquid at a high temperature. White scales and odour of frankincense. Silky needles and irritating fumes. White fumes and white crystals. White amorphous sublimate. (c) The sublimate is yellow. Yellow and red sublimate and green flame at mouth of tube. Reddish-brown drops, yellow when cold. (d) The sublimate is blue or Mack. Blue. Dull black, red when rubbed. Violet vapours are evolved and a metallic- looking blue-black cr} 7 stalline sub- limate is formed. Confirm for Hg, As aiud Cd by heating some of the dry substance in an ignition tube with Na 2 CO and a little charcoal powder. Metallic globules or mirror. A black metallic mirror. A metallic mirror and brown sublimate. 8. The substance readily fuses and gives off moisture. The moisture turns red litmus paper blue. The moisture reddens blue litmus paper. It also intumesces or swells up. As.,O 3 . Se0 2 . HgCl a . Sb 2 O 3 . PbCla. MoO 3 . Benzole acid. Succinic acid. Oxalic acid. Te0 2 . P. S and polysulphides. Indigo. HgS. I. (lodoform, etc.) Hg. As. Cd. Certain hydroxides and hy drates. NH 4 compounds. Free acids, such as HC1, HN0 3 , H,S0 3 , H 8 SO<, etc. , or of acid salts. Salts with water of crystal- lization, e.g., alums, phos- phates, borates, etc. 8 4 TABLES FOR QUALITATIVE CHEMICAL ANALYSIS Results. Inference. 9. (a). The substance gives off a colourless, odourless gas. The gas re-inflames the glowing end of a match. It supports combustion. The gas does not support combustion. The gas does not support combustion. Dip a glass rod into lime-water and lower it into the test tube ; the lime- water becomes turbid. Pass the gases through Ca(OH) 2 sol. The issuing gas burns with a blue flame. ) The gas possesses odour. The gas smells of NH 3 and turns red litmus paper blue. Confirm for NH 3 by warming the substance in a test tube with KOH solution. Smells like stale eggs and blackens paper moistened with lead acetate. A gas with a suffocating odour which reddens blue litmus paper. Confirm for SO 2 by lowering a rod mois- tened with K 2 CrO 4 into the test tube, a green colour : SO 2 . A gas with garlic odour, burns with a green flame. A fetid smell of CS 2 . The odour of bitter almonds, and burns with a peach-coloured flame. Oxygen from peroxides, chlorates, perchlo rates, nitrates, bromates, and i o d a t e s ; NO from NH 4 NO 3 . N,O from NH 4 NO ; ,, or a nitrate in the presence of an ammonium salt. N from NH 4 NO 2 , or a nitrite in the presence of an ammonium salt. Carbonates ; oxalic, benzoic and succinic acids, etc. CO and CO 2 from the de- composition of oxalic acid, oxalates, and form- ates. Ammonium salts ; from the cyanates in the presence of H. 2 O and from nitro- genous organic matter. SHa from hydrated sul- phides and hyposulphites in the presence of moist- ure. SO 2 from sulphites ; or hy- posulphites, sulphates and from metallic sul- phides and thiocyanates. PH 3 from phosphites and hypophosphites. Certain thiocyanates. Cy from cyanides of Ag, Hg, Cu, Zn, and from cy- anates and thiocyanates. TABLES FOR f \ QUALITATIVE Ti CHEMICAL ANALYSIS Results. Inference. Confirm for Cy, when CO 2 is also present, by passing the gases through lime- water and igniting the Cy. (c) It gives off a coloured gas. f Brown fumes of N 2 O 4 mixed with oxygen. A yellow-green gas with peculiar smell ; bleaches litmus, and turns KI and starch paper blue. Brown fumes with peculiar odour. Brown fumes condensing to red liquid. Purple vapours and sublimate. A vapour condensing to yellow or brown drops and burning with a blue flame. White fumes of HC1 or SO,. Nitrates of the heavy metals, such al"Pb, Bi, etc. Cl, from chlorides of Pt, Au, etc., also from certain chlorates and h y p o- chlorites. Br from bromides and some bromates. Chromyl chloride, from chloride and chromate. I from iodides and some iodates. S, from certain metallic per- sulphides, as PtS 2 , Au 2 S 3 , Sb 2 S 5 , SnS 2 , FeS 2 , etc. From certain chlorides and sulphates. Experiment II. Heat a little of the substance on charcoal before the . blowpipe, in the outer flame. Results. Inferences. \. The substance decrepitates. 2. It deflagrates. 3. It fuses readily and is absorbed by the char- coal or forms a fluid bead. 4. An infusible white residue is left, very luminous when strongly heated. The residue turns moistened red litmus paper blue. NaCl, KNO 3 , Pb2NO 8> etc. Nitrates, chlorates, bro- mates and iodates. Alkali salts and certain salts of the alkaline earths. BaO, SrO, CaO, MgO, A1 2 O 3 , ZnO and SiO 2 . Also ZrO 2 , ThO,, etc. BaO, SrO, CaO, MgO. 86 TABLES FOR QUALITATIVE WKMICAL ANALYSIS Experiment III. When the white infusible residue is cold, add a drop of Co2N0 3 and again ignite strongly. Results. Inferences \ A blue coloured mass is left. A pale pink-coloured mass is left. A bluish gree^i-coloured mass is left. A pale green-coloured mass is left. A violet-coloured mass is left. A1 2 O S , phosphates of Ca, Sr and Ba and many silicates. MgO. SnO., ZnO, Ti(X Phosphate of magnesia, Mg 8 (P04) 2 . 5. A coloured residue is left. The residue is black. And is attracted by the point of a mag- netised pen-knife blade.* Confirm. Transfer the particles to a piece of filter paper laid on glass, add a drop of dil. HC1 and of HNO 3 . Dry carefully over a flame ; a pale pink tint which turns to blue : Co. A greenish tint changing to yellow : Ni. Add a drop of K 4 FeCy (i , a blue colour : Fe. Fe, Ni, Co, Mn, Cr, Cu, etc. Fe, Ni, Co. Experiment IV. Prepare a clear colourless bead of borax in a ring or loop of platinum wire about 3 or 4 m.m. (or % inch) in diameter, then take up a small quantity of the powdered substance by dipping the hot bead into it and re-fuse. 1. Heat in the outer or oxidizing blowpipe flame. 2. Heat in the inner or reducing blowpipe flame. Or the bead may be fused in the corresponding areas of the bunsen flame, f but the results are not always satisfactory. Colour of Bead. Amethyst. Blue. Brown. Green. Pink. Red. White. Yellow to brown, Colourless. /;/- the Oxidizing Flame. Mil, Di (Co mixed with Ni) Co, hot and cold ; Cu cold. Ni hot and cold. Cr, Cu (hot), V (cold), U. Di. Ce, Fe ; Ni (brown cold). Ag, Zn. Fe ; U, Pb, Bi, Sb, V, Mo (hot). Ag, Al, Ba, Ca, Cd, Nb, Pb,Sb, SiO,,Sn (turbid), Sr, Ta, Te, Ti, W, Zn. In the Reducing Flame. Ti, cold. Co, hot and cold; Nb. Mo. Fe, U, Cr, V. Di. Cu (opaque when in excess) Ag, Bi, Cd, Nb, Ni, Pb, Sb, Te, Zn. Ti, W, V, Mo (hot). Al, Ba, Ca, Ce, Cu, Di, lyi, Mn, SiO,, Sn, (turbid), Sr, Ta. Confirm for Mn and Cr by fusing on Pt foil with Na. 2 CO 3 and KNO 3 , a blue residue : Mn ; a yellow residue : Cr. *Magnetise the blade of a pen-knife by drawing a magnet over it 4 or 5 times in the same direction. TABLES FOR Q IVK CHEMICAL ANALYSIS Experiment F Flame tesE^Take up a little of the substance on a very thin platinum wire moistened with cone. HC1 and heat it at the base of the bunsen flame. Results. l * *^ f m Inferences. The flame is coloured bright yellow. Na. ,, ,, ,, yellowish-red, n M t> re d. . * . ,, ,, ,, crimson. ,, ,, ,, pale green, green. ^^ ft. ^ ; , Ba and phosphates^^^L Cu, B,0 3 - deep greer^^ Tl. ,, ,, ,, vivid blue. Cu. bluish-grey. g^ As, Sb, Pb. ,, ,, ,, lavender. K, Confirm for borates ; heat the substance , moistened with a little H^SCX on a clean platinum wire : green colour. Confirm for K ; view the flame through blue glass : lilac to red colour. II , ^Experiment VI Heat the substance on charcoal in the inner flame. Results. Inferences. t A white incrustation is formed on the charcoal. A white incrustation far from the test and an odour of garlic is emitted. A white incrustation with slight acid odour. A yellow incrustation when hot, white when cold. Confirm for Zn ; moisten with Co2NO 3 and heat again : green colour. A reddish-brown incrustation readily volatilized. A dark red incrustation ; an offensive odour as of decaying horse-radish. HgCl,. As. Te. Zn. Zn. Cd. Se. 88 TABLES FOR QUAI^ITAT CAL ANALYSIS fusion mixture) and KCy and heat Experiment VII Mix with NaK( on charcoal in the reducing- flame. Alternative method. Flatted out a small piece of Na, wrap the sub- stance in it, and heat on charcoal before the blowpipe. ^J^rape out, with a magndfcsed penknife blade, into a small mortar, grind with water; wash away the cjj^rcoal powder and examine for metallic particles. cliai Results. Inferences. -4 ueed to the metallic state. ') With incrustation White malleable beads : slight yellow in- crustati^Ph, white when cold. Bluish-white malleable beads which mark paper ; pale yellow incrustation when cold. White brittle beads with acicular crystals of Sb. 2 O ;5 . Copious white fumes and incrustation. Pale reddish brittle beads, dark orange incrustation when hot, yellow when cold. (b)~Without Incrustation White malleable metallic beads. Confirm for Ag ; dissolve in HNO 3 , add a dtop of HC1 : white ppt. of AgCl, which darkens on exposure to light. Grey metallic particles ; non-magnetic. " Yellow metallic beads. Malleable particles or beads of red metal Black metallic infusible powders ; mag- netic. Test for S by scraping out some of the fused mass and placing it on a silver coin with a drop of water : a black stain of AgS left. Sn. Pb. Sb. Bi. Ag. Pt. Au. Cu. Fe, Ni and Co. S from sulphates or sul- phites. Experiment VIII Match test Hold a piece of crystallized Na 2 C03ioH 2 in the flame until it begins to fuse superficially, rub the untipped end of a wooden match in this until the wood is saturated with Na^CO*, char this end of the match and then dip it into the finely-powdered substance and heat it again in the upper reducing area of the bunsen flame. Grind the product with water in a mortar and search for metallic particles. TABLES FOR Results. Malleable metallic CHEMICAL ANALYSIS 8 9 Inference. bluish- white. yellow. red. Brittle metallic particles white. A. pink tinge. Magnetic particles. 4 Confirm in each case by dissolving in acids and applying special testj Ag, Sn. Pb. Au. Cu. Sb. Bi. re, Co, Ni. Experiment IX Film test. Heat the substance on a few fibres of asbestos, in the upper part of the bunsen flame so placed under a porce- lain basin of cold water (supported on a retort stand) that any volatile matter may be condensed upon the cold porcelain. In upper reducing flame. Upper oxidizing flame. Inference. ^ 1. Metallic Film 2.*^ *&e Film ~m Grey Film Vv Hg- / Metallic lustre White As \ Black film Yellow Cd. * C Brown ,, ,, White Zn. ,, ,, i Sn. Velvety black ,, Sb. Black Pale yellow Bi. ,, White Te. Cherry-red Se. Experiment X-Expose the above films to the vapour of iodine by volatilizing- some iodine from a few threads of asbestos, and afterwards to SH 2 or (NH 4 ) 2 S. The film is coloured. TABLES FOR QUALITAT Upper At, ANALYSIS In upper reducing flame. ' 3. Iodide Film Red or yellow Yellow N Brown Iphide Film Black Bt A Yellow Brown to black Pale yellow White 'Brown or yello Orange Yellow Brown Brow Inference. Hg. As. Pb. Cd. Zn. Sti. Sb. Se. Bi. Te. Experiment XI Boil some of the powder in a test tube with NaOH. Results. Inference. Smell of NH 3 and white fumes of NH 4 C1 when a rod moistened with HG1 is lowered into the tube. Presence of NH 4 salts. o . J) PREPARATION OF THE SOLUTION. Water. Boil about '5 gm. of the finely-powdered substance with dis- tilled water, and decant the clear solution from any insoluble residue ; repeat the process as long as anything is' dissolved, ascertained by evaporating a drop of the solution in a watch-glass or on platinum foil. See Table of Solubilities. Acids. The residue insoluble in water is first treated with boiling dilute HC1. If insoluble in dil. HC1, try strong HC1, and if insoluble in this use HNO 3 upon a fresh portion of the substance. Notice whether CO 2 , SO 2 , HCy, or Cl are given off, also whether S, I, SiO 2 , benzoic acid, etc., are precipitated. If insoluble in HNO 3 alone, add 3 vols. of strong HC1. When aqua regia is used, employ it in successive small quantities ; the iodide, bromide, cyanide, ferrocyanide, and ferricyanide of silver are decom- posed by boiling wdth aqua regia. TABLES FOR QUALITATIVE CHEMICAL ANALYSIS 9J The aqueous and acid solutions may be mixed and examined together ; but they must be examined separately when it is wished to learn how the acids and bases are combined in a complex mixture. ^** Insolub/e.The residue insoluble in acids must be carefully with distilled water to remove acids, ^ried and tested by the Table for Insoluble Substances. A residuum or precipitate may* be due to the preJftce of sulphur or sulphides, iodine from iodides in the presence of- oxidizing substan iodates in the presence of reducing agents ; AgCl, Hg 2 Cl 2 , may have originally existed in the mixture or may have been formed by the action of acids ; silicic, tungstic, titanic, and molybdic acids may have been r set free from their compounds. Impossible, discriminate^between insoluble substances originally present and those whichare precipitated on continued boiling with strong acids. See special Table for Insoluble Substances. Insoluble cyanides The presence of insoluble double cyanides may be suspected when HCy, although not found in the preliminary examination, is found on treating the substance with H 2 SO 4 . Examine by the Table for Insoluble Cyanides. METALS AND ALLOYS. If the substance be a metal or an alloy, first reduce it to filings or thin sheets ; if very brittle it can be roughly powdered on an ativil with hammer ; to prevent the loss of fragments, wrap the substance in stron brown paper. If it is not quickly dissolved by boiling HC1, it can be at once treated * with HNO 3 of sp. gr. i '2(1:1 aq.), and if this act but slowly some strong HNO 3 of sp. gr. i '4 can be added ; if there still be a residue, filter and wash. Solution. May contain traces of Au and Sb, also As as oxide ; other metals will be present as nitrates, and their examination can be proceeded with in the usual way, after evaporating off most of the HNO 3 . Residue. May contain metallic Au and Pt, test for these separately ; Sb and Sn as oxides or arsenates, Pb2N0 3 , which is insol. in strong HNO 3 , and Bi as arsenate or phosphate. If this residue be white then probably only Sn and Sb as oxides are present. Strong HC1 converts metastannic acid into metastannic chloride which is soluble in water, but insol. in cone. HC1. 92 TABLES FOR QUAIjTATlV^CHtfytlCAL ANALYSIS Boil the residue with a strong sol. of Tartaric acid, and filter. Residue SnO 2 . -.Reduce > -P CC ^S 0) o;aj ^^ fe I-IKS .-,^bobJO '^'o^o ./goac rt^fr! ?i | ; K*S S ^tZ J2 .^ ** ^3 03 a I g ife u $5 oil o -. *'- rt S ^^ ^S -2 Jgj S2 &| .S^tl .S-3-Snd ^rdR, 5/? >J g a * ^m a ^.^ 8 h rt 2 5 ^ ^ w li SSiSii Sg.?|!!.lj Illi!i4i| -5^ ii^ijl nee of Mercury. ^u 1/3 _d . d -S cij Residue. lute (NH 4 )OE " >3 H"-< d -2^o3bcd dS*a#B.sS- Piiiiiti IlB!i"ii 1 AH T3 S p^ 5^ S^2 S CO S rf o w ^ t o ,-. -a Z " I Sf "^ I Q * O 95 jji a v*R w s ifllal , = .i 3 W a-s rd 8 .S '5 in - * II, a "5 AH rt H a a 03 - 1 08 1 3 o o la 'S a .a o S^ fn -K > D 1 8 I 5 1 1 s ^ * 53 - Is c y SB .2 S I * oj II o S "^ H EXAMINATION FOR BASES 97 03 rrt o - s.s -2a f Mi. 5 S* & ?5f 8.fl " ^^ rH P t{ 3 w "d -d 03, nd 9 " I _, d IH ,0 r^ O u& o a - eg ^ Mil " Sj,d ^^-S ^ II 8a 2 o s-a a 10 . ^ 98 EXAMINATION FOR BASES s w PH t> O ,4 W M O t ( o >^ o' -g-sg 3 d'W ' ft 1 Ss ICJ'- 1 il 11 f fpj W O rt < h4 PQ 5 and ignite on pei relied. A yellow Presence of So I fl 0) 0) ^1 CL) g ^-T'o; 43 i- 0^0 J W< f^ ^ MH "*-" o . o il 1 I ^ 8 8 03 03 CU H a " |'S n down as phosphat 1 P |5 I S o 10 o3 0) '^ X ?3 | I r3 $ 0) p ^ s ! 5 1 II 11 ll >H Cfl o3 en 1 1 i 03 a H *, o ~ W ^ en o Yy ~^ -M Jjh PH i OJ a > o> W s w J ^ tn ^'S | fc'JS 1 H ll '^< i O THE EXAMINATION FOR ACIDS. (Acid Radicles or Anions.) After the bases have been detected, refer to the Table of Solubilities (see index) to ascertain what acids form insoluble compounds with the bases present all such acids must necessarily be excluded if the substance is a soluble one. The acids, unlike the bases, cannot all be detected and separated in systematic order ; the presence of each acid must be confirmed by its most characteristic special tests. Several of the acids should have been detected during the preliminary examination when testing for the bases, e.g., CO 2 , SH 2 , H 2 SO 3 , HC1O, HC 2 H 3 O 2 , H 3 AsO 3 and many others. The presence of such organic acids as tartaric, citric, benzoic and succinic, should also have been more or less definitely ascertained. PRELIMINARY TESTS FOR ACIDS. 1. Warm the powder in a test-tube with dilute HC1. Results. Inference. Gases are given off A colourless gas with but faint smell is evolved, which renders lime-water turbid. Use a glass rod for the Ca(OH) 2 . Ditto, having the suffocating odour of burning sulphur. Turns K 2 Cr 2 O 7 sol. green. Ditto, with separation of sulphur. Ditto, with odour of stale eggs, and blackens lead acetate paper. Ditto, with the odour of bitter almonds. Reddish-brown fumes. A yellow-green gas, of suffocating odour, which bleaches indigo and other vegetable colours. CO 2 , from carbonates, and from cyanides and cyan- ates containing carbonates SO 2 , from sulphites. SO 2 , from thiosulphates. H 2 S, from sulphides, except Au 2 S 3 , PtS 2 , Ag a S, HgS, CuS, Bi 2 S 3 , and As 2 S 3 ; these however give off H 2 S in presence of zinc and HCL* HCN from cyanides. NO and NO 2 from nitrites. Cl, from hypochlorites. * S in insol. sulphides and sulphates is best detected by the match and silver coin tests. 101 102 EXAMINATION FOR ACIDS 2. Warm a portion of the substance with H 2 S0 4 (i add to i water). Results. Gases are given off Smell of vinegar. Add i c.c. alcohol : ethyl acetate odour. Strong acid fumes. Inference. CO 2 , H 2 S, SO 2 , NO, and HCN, have already been detected by means of dil. HC1. Acetates. Ditto. HC1, HF (HCN from ferro- and ferricyanides) H 2 S 2 O 3 , HC1O, HCNO. 3. Warm with a few drops of cone. H 2 S0 4 (the heat must not be sufficient to drive off the H 2 S0 4 ). Colourless gas evolved With irritating odour, gives white fumes with NH 3 . Add MnO 2 : Cl. Corrodes glass. CO evolved without blackening. CO and CO 2 evolved. Absorb CO 2 by Ca(OH) 2 and burn the CO. Peculiar odour, mixture of H 2 S, SO 2 and HCN with precipitation of S ; fumes redden paper moistened with FeCl 3 . CO, CO 2 , SO 2 and odour of burnt sugar ; the substance also blackens, tartaric acid chars rapidly, citric but slowly. The gas re-ignites a glowing splinter. Coloured gases are evolved Violet vapours which turn starch paper blue. Reddish-brown vapours which turn starch paper yellow. Greenish-yellow gas with small explo- sions. Brownish-yellow irritating vapours. Confirm for HNO 3 by adding fragments of Cu : red fumes. HC1. HF. Formic acid. Oxalic acid. Thiocyanates. Tartaric and citric acid. Oxygen from chromates, permanganic acid, per- oxides, and other easily decomposed compounds rich in oxygen. Iodides (and iodates in pre- sence of reducing agents). Bromides and bromates. Chlorates. Nitrates. EXAMINATION FOR ACIDS 103 N.B. In treating with acids, amongst the substances which may separate out are the following : Results. Inference. White sulphur (with H 2 S). Yellow ,, (withSOa). Iodine Colourless gelatinous silica. Confirm for SiO 2 by microcosmic salt bead. Yellow (when hot) tungstic acid. White molybdic acid, soluble in an excess of acid. White TiO-2. Confirm by adding a fragment of Zn and diluting Violet colour : Blue turning to brown : Blue-green turning to brown : Boracic, benzoic, succinic, uric, and other acids separate out from concentrated solutions. From polysulphides. From thiosulphates, poly- thionates. From iodides in presence of oxidizing, and from io- dates in presence of re- ducing bodies. From silicates. Tungstates. Molybdates. Titanates. Titanic acid. Tungstic acid. Molybdic acid. PREPARATION OF THE SOLUTION. As many of the bases interfere with the reactions of the acids, it is necessary to remove them before proceeding to test for the latter. Therefore boil a portion of the original substance with pure Na 2 CO (free from SO 4 and Cl) which precipitates nearly all the metals, except the alkalis, as carbonates ; filter and add to the filtrate a few drops more Na 2 CO 3 , if no further precipitate is thrown down boil the solution, now containing all the acids as salts of sodium. But if H 3 As0 3 , H 3 As0 4 , H 2 MoO 4 , H 2 WO 4 , H 2 SeO 4 , H 2 TeO 4 or H 2 CrO 4 have been found amongst the bases, first pass the SH 2 through the slightly acid solution and filter ; warm the filtrate to drive off excess of SH 2 and neutralize with NH 4 OH, and then remove any bases of Groups III, IV and V by NaaCO 8 . as before. 104 EXAMINATION FOR ACIDS Divide the solution into 4 parts. (a) Acidify one portion with dilute HC1. (d) Acidify another portion with dilute HN0 3 . (c) Acidify the third portion with dilute HC 2 H 3 2 . (d) Neutralize the fourth portion with dilute HC 2 H 3 2 . (). HC1 Solution. Add BaCl 2 sol. a. A white ppt. insol. in boiling HC1 b. Filter, if necessary, and add Br aq., a white ppt. c. A white gelatinous ppt. which evolves SiF 4 , on warming with H 2 SO 4 Add FeCl 3 sol. a. A blood-red colour, destroyed by HgCl 2 b. A dark-blue ppt. (Prussian blue.) c. A brown or green solution Confirm for H 3 FeCy 6 by FeSO 4 : deep blue ppt. If both H 4 FeCy 6 and H 3 FeCy 6 are present, filter off the ppt. reduced by FeCl 3 and add H 2 SO 3 to the filtrate, a blue ppt. : H 2 S0 4 : : H 2 SO 3 or H a S 2 O 8 . : H 2 SiF 6 . HCyS. H 4 FeCy 6 . H 3 FeCy 6 . H 3 FeCy ( , (b). HN0 3 Solution. Adfl AgN0 3 sol. A white or yellowish ppt. sol. in NH 4 OH : AgCl, AgBr, AgCy, AgBrO 3 or AgIO 3 . a. AgCl (white). Confirm by MnO 2 and H 2 SO 4 , Cl evolved, which bleaches litmus paper. b. AgBr (yellowish). Confirm by MnO 2 and H 2 SO4 : red fumes, or by Cl and CSa : red-brown colour. c. AgCy (white). Confirm by igniting on porcelain, metallic silver is left. d. AgBrO 3 (white), crystalline. e. AgIO 3 , white ; H 2 SO 3 converts it into yellowish Agl : HC1. : HBr. : HCy. : HBrO 3 . : HI0 8 . (c). Acetic Acid Solution. 1. Add CaCl 2 sol. A white ppt. This may be due to HF, H 2 C 2 04 or H 4 FeCy 6 . EXAMINATION FOR ACIDS 105 2. Add AgNO sol. A pale yellow or white ppt. insol. in NH 4 OH. a. Agl. Warm with MnO 2 and H 2 SO 4 , violet vapours. Add Cl aq. and CS 2 : purple sol. b. A white ppt. of AgCyS c. A reddish-brown ppt. d. A black ppt. Test the original sol. with Na nitroprusside : a violet colour HI. HCyS. H 3 FeCy 6 . SH 2 or a soluble sulphide. W Neutral Solution. 1. Add AgNOs sol. I. A white ppt. sol. in NH 4 OH. a. From strong sols. b. The original sol. does not coagulate albumen c. The original sol. coagulates albumen d. The ppt. becomes grey on boiling e. The ppt. blackens on boiling f. On warming becomes grey Malic acid yields a white ppt. with Pb2C 2 H 3 O 2 , which melts on boiling the liquid. g. On warming : metallic mirror h. The sol. in NH 4 OH on warming yields a mirror. The original sol. (neutral) : a ppt. with CaCl 2 Tartarie and Citric Aeids. Precipitate the tartaric acid by a strong sol. of K acetate in alcohol, add acetic acid, stir well and allow to stand. Filter off the KHC 4 H 4 O 6 boil off the alcohol and add BaHoO 2 or Ba acetate : a white ppt. Other acids also give white ppts., e.g., thiocyanic, hydroferrocyanic. See (b) HNO 8 solution. II. A coloured ppt. sol. in NH 4 OH. a. Yellow. Confirm for P 2 O 5 by (NH 4 ) 2 MoO 4 b. Pale yellow c. Brown d. Red e. Orange H 8 B0 8 . H 4 P 2 7 . HP0 3 . H 2 SO 3 . H 2 S 2 3 . Oxalic and malic acids. HCHO 2 . Tartaric acid. Citric acid. H 3 P0 4 . H 3 As0 3 . H 3 AsO 4 . H 2 Cr0 4 . H 4 Si0 4 . 106 EXAMINATION FOR ACIDS 2. Add FeCl 3 sol. a. A red colour, destroyed by boiling and a brown basic salt precipitated b. A violet-red colour destroyed by boiling c. A pale yellow ppt. of basic ferric benzoate d. A reddish brown ppt. of basic ferric succinate : HCHO 2 and HC 2 H 3 2 . : H 2 S 2 3 . : Benzoic acid. : Succinic acid. To distinguish between benzoie and sueeinie acids. Boil the mixed pre- cipitate with NH 4 OH, filter, add alcohol and BaCl 2 , white Ba succinate is thrown down. Benzoic acid does not give a precipitate. To detect HCN in the presence of HC1, wash the Ag precipitate obtained in the HNO 3 sol. (b) and ignite on a piece of porcelain. Dissolve the metallic Ag left by the AgCN in nitric acid, and test for Ag in the solution with HC1 as usual. To detect HBr in the presence of HC1. Distil the dried chloride and bro- mide with K 2 Cr 2 O7 and H 2 SO 4 . Remove the Br from the chromyl chloride in the distillate by means of ether. To detect HC1 in the presence of HI. Digest the mixed Agl and AgCl ppts. with NH 4 OH, filter ; the Agl is insoluble. Dilute HNO 3 reprecipi- tates the AgCl from the filtrate. The pale yellows of Agl and AgBr are not always visible when mixed with white precipitates, hence very little importance can be attached to the colour of the precipitate obtained on adding AgNO 8 . To distinguish between HC1, HBr, and HI. Precipitate the HI as Cu 2 I 2 by means of CuSO 4 and H 2 SO 3 ; filter, remove the CuSO 4 by pure NaOH, evaporate the filtrate to dry ness, and test for Cl by K 2 Cr. 2 O 7 and H 2 SO 4 , and for Br by Cl water and ether, CHC1 3 or CS 2 . Or dissolve out the AgCl by boiling with (NH 4 ) 2 CO 3 ; add a little Cl water and starch paste to the residue, a blue colour : iodine. To another part add an excess of Cl water to oxidize the iodine, shake with CS 2 , a brown colour : bromine. To distinguish between chloride and chlorate. Precipitate the chloride by AgNO 3 , filter off the AgCl. Reduce the chlorate to chloride by zinc and H 2 S0 4 , then add AgNO 8 : AgCl. To distinguish between HC1, HBr, HI and HCN. Test for HCN by treat- ing the mixture in a dish with dilute H 2 SO 4 , covered with an inverted porcelain dish containing a drop of (NH 4 ) 2 S or AgNO 3 , to absorb the HCN ; the NH 4 CNS formed will give the blood-red colouration with FeCl 3 , and the AgNO 3 a white precipitate of AgCN. EXAMINATION FOR BASES A white or slightly yellow precipitate may contain silver salts of HC1, HBr, HI, HCN, H 4 FeCy 6 , HIO 3 , HBrO 3 ; and if orange, H s FeCy 6 in addition. To distinguish between hypoehlorites and chlorates. Add NaOH and then MnSO 4 : brown ppt. of MnO 2 .H. 2 O, due to the oxidation by the hypo- chlorite. Filter, and decompose the NaCl thus formed in the solution from the hypochlorite by AgNO 3 sol. Filter off the AgCl and add Zn and H. 2 SO 4 to the filtrate (to reduce the chlorate to a chloride), filter and add AgNO 3 , a white ppt. of AgCl indicates the former presence of a chlorate. To distinguish alkaline cyanides, ferroeyanides, ferrieyanides and thio- eyanates. Saturate with CO. 2 and distil off the HCy ; add excess of FeCl s to the residue in the flask, a precipitate of Prussian blue : ferroeyanide. Filter, a red filtrate shows the presence of thioeyanates ; add FeSO 4 : a precipitate of Turnbull's blue : ferrieyanide. Cyanide, chloride, bromide, iodide, ferroeyanide, ferrieyanide, and thiocyanate. Precipitate with AgNO 3 , filter and ignite ppt. (all except the haloid compounds are decomposed). Fuse the ignited ppt. with Na 2 CO 3 , digest with boiling water and test the solution for Cl, Br, and I in the usual way. To detect a soluble sulphide, thiosulphate, sulphite and sulphate in a mixture. Add CdCO 3 and agitate, extract with dil. acetic acid and filter. A residue of CdS (yellow) indicates the presence of a soluble sulphide. Filtrate. Add BaCl 2 to the cold solution. Precipitate : BaSO 4 and BaSO 3 , warm with dil. HC1 and filter. Residue. BaSO 4 : sul- phate. Filtrate. Add Cl wa- ter, a white ppt : sulphite Filtrate contains thiosulphates. Add HC1 and warm, a white ppt. : thiosul- phate. To detect a soluble sulphide in the presence of free SH 2 , add a drop or two of Na nitroprusside : a purple colour. INSOLUBLE SUBSTANCES. The residue left after treatment with HC1 and HNO 3 may contain the following: Carbon and chrome-iron (black), sulphur, Agl and PbCrO 4 , (yellow); certain double cyanides, SiO 2 and most silicates, AgCl, AgBr, PbCl 2 , PbSO 4 , SnO 2 , Sb 2 O 4 , BaSO 4 , SrSO 4 , CaSO 4 , CaF 2 and other fluorides, certain arsenates and metaphosphates (white). Ignited A1 2 O 3 (white), Cr 2 O 3 (green), and Fe>O 3 (brown). A few of the above are slightly soluble in acids and should have been already found in the solution, e.g., PbCl 2 , PbSO 4 , PbCrO 4 , Fe 2 O 3 ,CaSO 4 , fluorides, arsenates and some others. PRELIMINARY TESTS. a. The insol. residue is white. 1. Moisten with (NH 4 ) 2 S solution, it blackens : Ag-, Pb salts. 2. Heat in an ignition tube, it fuses : Ag- and Pb salts. It is infusible and remains white : Si0 2 , (PbS0 4 ), A1 2 8 , BaS0 4 , SrS0 4 , CaS0 4 , CaF 2 . 3. Exposed to sunlight it becomes slate-coloured : AgCl. 4. Confirm for Pb and Ag by the blowpipe on charcoal : white malleable beads. 5. Confirm for SiO 2 in the microcosmic salt bead ; a skeleton of Si0 2 : silicates. 6. Confirm for Al 2 O 3 by heating on platinum wire with Co2NO 3 solution ; a blue residue : A1 2 3 . 7. Confirm for Ba, Sr, and Ca, by the flame test with HC1 ; apple-green colour : Ba ; crimson : Sr ; brick-red : Ca. b. The insol. residue is yellow. Heat in an ignition tube ; it fuses, SO 2 evolved and yellow drops sublime : S. Infusible, darkens on heating : Sn0 2 , Sb 2 4 . Confirm for Sn and Sb on charcoal or by match test ; malleable beads : Sn ; brittle hard beads : Sb. c. The residue is green. Fuse in borax bead ; green colour : Cr 2 O 3 . 1 08 INSOLUBLE SUBSTANCES 109 d. The residue is brown or black. Infusible, leaves magnetic residue when heated on charcoal : Fe 2 O 3 . Black residue burning entirely away. Confirm by igniting with KNO 3 on Pt foil ; it scintillates : C. TREATMENT OF THE INSOLUBLE RESIDUE. 1. If C or S has been detected, the residue must be ignited in an open crucible. 2. Certain substances, if present, may be dissolved out by special reagents, and tested for separately, viz. : AgCl, AgBr, Agl, soluble in strong KCy. PbCl 2 soluble in boiling water. PbSO 4 soluble in ammonium acetate. 3. The dry residue is mixed with four times its bulk of fusion mixture (Na 2 CO 3 ,K 2 CO 3 ) and fused in a Pt crucible (or on a piece of Pt foil turned up at the edges) over a bunsen burner until all effervescence ceases. 4. If compounds of easily reducible metals (Ag, Pb, Sb, Bi, etc.) are present, they must first be removed by suitable solvents, because the above metals form easily fusible alloys with Pt ; or the fusion may be made in a small porcelain crucible, on a crucible lid, or on a piece of a broken porcelain dish. The silica of the porcelain is attacked by the fusion mixture, hence if SiO 2 has been indicated in the preliminary tests, fuse on Pt after removing the Ag, etc. A nickel crucible can be used in most cases. Dissolve the fused mass in hot water. Filter. Residue. Contains the bases. (a). If Ag or Pb has been found extract with HNO 3 . (). If Ag and Pb are absent, ex- tract with HC1. Filter and wash. Filtrate. Contains the acids. Neutralize with HNO 3 and boil. If SiO 2 be present, evaporate to dry- ness, take up with HNO 3 and filter hot. Residue. Filtrate. Residue Filtrate. Examine for SnO 2 , Sb 2 O 4 , CaF 2 , Ag, Pb, Sn, Sb, acids. HC1, HBr, HI, and chrome iron. Al, Fe, Cr, Ba, SiO 2 . H 2 S0 4 , H 2 Cr0 4 , H 3 P0 4 , Confirm for each by special tests. Sr, Ca. Examine by the Tables in the H 3 AsO 4 , HF, all of which should have been found in the preliminary tests. usual way. no INSOLUBLE SUBSTANCES DETECTION OP ALKALIS IN SILICATES. Mix *5 gram of the finely-powdered silicate with 2 grams of NH 4 F and a little strong H< 2 SO 4 to a paste on platinum foil ; heat at a very low temper- ature as long as fumes of SiF 4 are evolved, then raise the heat to drive off the H 2 SO 4 . Dissolve the residue in water and test for alkalis on Pt. wire in the usual way. A second method is to grind '5 gm. of the already finely-powdered mineral with 'i gm. NH 4 C1 and 4 gms. pure CaCO 3 ; then heat to bright redness on platinum foil for 20 to 30 minutes. When cold, boil crucible and contents in about 50 c.c. water, filter (the residue consists of CaO, SiO 2 , etc. , and need not be examined), to the solution add (NH 4 ). 2 CO 3 to precipi- tate the CaCL 2 , filter and wash, evaporate the filtrate to dryness and test for the alkalis in the usual way. TREATMENT OP INSOLUBLE DOUBLE CYANIDES. The simple cyanides are converted into chlorides by boiling with strong HC1, but AgCN, Ag 4 FeCy 6 , and Ag 8 FeCy 6 require to be boiled with aqua regia. To detect an insoluble cyanide boil some of the residue insoluble in HC1 (left by the original substance) with NaOH, filter, acidulate the filtrate with HC1 and test it for H 4 FeCy 6 and H 3 FeCy c ; if either are present, proceed as follows : a. Boil one part of the substance with NaOH ; filter. Residue. Diss. in HC1 and ex- amine for bases in the usual way, except Na, K. Solution. May contain H 4 FeCy c and H 3 FeCy 6 ; also such bases as PbO, ZnO, and A1. 2 O 3 soluble in NaOH. Pass SH 2 to remove PbO and ZnO, filter, and test filtrate for H 4 FeCy 6 and H 8 FeCy 6 with FeCl 3 and FeS0 4 . b. Fuse another portion with four times its bulk of a mixture of one part NH 4 NO 3 , and three parts (NH 4 ) 2 SO 4 . Dissolve the melt in HC1, remove heavy metals in the usual way, and test for K and Na. Test for acids in the solution as in a. APPENDIX. TESTS FOR CERTAIN ELEMENTS IN CARBON COMPOUNDS. (See also Preliminary Tables, p. 82 and p. 101.) To detect hydrogen, nitrogen, sulphur, &c., in carbon compounds : 1. Hydrogen. Mix the substance with dry CuO and heat in an ignition tube, water is given off and condenses in the cooler part of the tube : Hydrogen. 2. Carbon. The gas given off renders lime-water turbid (a drop of Ca(OH) 2 on the end of a glass rod is sufficient) : CO 2 from Carbon. 3. Nitrogen. Its. presence may be indicated by the odour of singed feathers when the substance is burnt. Mix the powdered substance with soda-lime and heat in an ignition tube, the odour of NH 3 : Nitrogen. NO 2 compounds do not give off NH 3 . 4. Sulphur and Phosphorus. i. Mix with pure Na. 2 CO 3 and pure KNO 3 or with Na peroxide and fuse in an ignition tube, dissolve out with water and test for H a SO 4 by BaCl 2 , and H 3 PO 4 by am. molybdate. 2. Ignite with a very little metallic Na, and dissolve in aq. Add a drop of Na nitroprusside to the clear sol. , a purple colour : Sulphur. 5. The Halogens. i. Heat a copper wire in the bunsen flame until it ceases to give a green colour to the flame, then dip it into the substance to be tested, a vivid blue flame indicates the presence of a halogen. 2. Mix with pure CaO, heat in an ignition tube, dissolve out with water, filter and test for HC1, HBr and HI in the usual way. TESTS FOR CERTAIN ORGANIC LIQUIDS. Heat a drop or two in a dry test tube. Results. It volatilizes completely. The vapour is non-inflammable, pleasant ethereal odour The vapour burns with a pale blue flame Inference. Chloroform. Alcohol, Aldehyde, Chloral, Carbon bisulphide, in 112 APPENDIX Results. Inference. The vapour burns with pale blue flame, with slight charring and unpleasant odour The vapour burns with luminous flame The vapour burns only on warming, smoky luminous flame The vapour is acid, pungent and inflam- mable Glycerol. Ether, Et. acetate, nitro- benzene. Paraffin oils, turpentine, benzene, aniline. Formic or acetic acids. TABLE OF SOLUBILITIES. 1 . All the salts of Li, NH 4 ,' Na, and K are soluble in water. 2. All normal nitrites, nitrates, hypochlorites and chlorates are soluble in water. If a compound is soluble in water it is usually soluble in dilute acids ; Ag, Hg', and Pb salts, however, yield insoluble chlorides with HC1, and many salts readily soluble in water are insoluble in concentrated acids, e.g., AgNO 3 in HNO 3 , BaCl 2 in HC1. Name of Salt. Soluble in Water. Sol. in, or decom- posed by, HC1 or HN0 3 . Insol. in acids. Acetates Arsenates and Arsenites Benzoates Borates Bromides Carbonates All sol. except some basic acetates (Ag and Hg' difficultly.) Of alkalis, and acid ar- senates of Ba, Sr, Ca. Of alkalis, Ba, Sr, Ca, Mg, Mn", Zn, Fe". Of alkalis. Many others are slightly sol. Of alkalis, Ba, Sr, Ca, Mg, Al, Zn, Mn, Ni, Co, Fe, Hg", Cu", Cd, Au, Pt (Pb slightly). Of alkalis. Basic acetates. Nearly all, (Sb ar- senate slightly) Ag, Pb, Hg x de- composed. Nearly all. All. Bi, Sb, Pb, Cu', and HgBr 2 in dil. HC1. All decomposed. Native FeCO 3 , MgCO 3 , and MgCa(C0 3 ) 2 , slowly. AgBr, HgBr. APPENDIX Name of Salt. Soluble in Water. Sol. in, or decom- posed by, HC1 or HN0 3 . Insol. in acids. Chlorides Of alkalis and of all AgCl, HgCl. metals except Ag, Hg' Cu', Au', Pt" ; PbCl. 2 .L/e -t-t sol. in boiling water. Chlorates All sol. * Chro mates Of alkalis, Sr, Ca, Mg, Nearly all. Ignited PbCrO 4 Zn,Mn,Fe'",Hg",Cu. Native Cr iron. Citrates Of alkalis, Mg, Al All. (mono), Cr, Cu, (Ba), Pb (di), Ca (tri), (Zn, - Ni, Co, Fe slightly). Cyanides Of alkalis, Sr, Ca, Mg, Fe" in hot cone. Hg", Au, Pt, (Ba HC1. Single slightly). cyanides; AgCN in aqua regia. Ferrocyanides Of alkalis, (Ba, Sr, Ca, Cd, Mn, in HC1 ; Both ferro- and Mg, Bi, slightly). most others in ferri- cyanides aqua regia. are d e c o m- Ferricyanides Of alkalis (Ca, Mg, Fe'", Pb, slightly). posed by boil- ing with KOH Fluorides Of alkalis, Cr, Ag, Pt, Nearly all. Fluorspar de- Hg". BaF 2 sol. inHNO 3 composed by H 2 SO 4 . Fluosilicates Of alkalis, K and Ba Of Ca, Ba. only slightly, Al, Cd, Cr, Ni, Co, Fe, Pb, Mg, Mn, Sn, Hg, Ag, Zn. Formates Nearly all sol., Sn" in- sol. Pb sol. in boil- ing water. Hydroxides Of alkalis, (Ba, Sr, Ca, Nearly all. si. sol.). Hypochlorites All sol. Ag. hypochlorite decomposed into chlorate and in- sol. chloride. Iodides Of alkalis (Pb slightly). Hgl slowly on Ag, Cu', Hg', boiling. Pb, Pt", (Hgl sol. in KI). Nitrates All except the basic Basic nitrates. nitrates. Nitrites' All sol. (Ag slightly), most basic nitrites insol. APPENDIX Name of Salt. Soluble in Water. Sol. in, or decom- posed by, HC1 or HN0 3 . Insol. in Acids. Oxalates Of alkalis, Cr, Sn iv , Pt, All sol. in HC1. (Mn slightly). Oxides Of alkalis, Ba, Sr, (Ca, SnOo and ignited Sb. 2 O,, SnO,, As, slightly). Fe.O 3 slightly. A1,O 3 and Ag, Pb, Hg sol. Cr 2 O 3 after , in HNO 3 . strong heating Pb 3 O 4 d e c o m- posed. Phosphates Of alkalis. All sol. in HNO 3 . (Ortho) Silicates Of alkalis. Most silicates are Many native sil- d ecomposed icates insol. with separation All are decom- of Si(OH) 4 . posed by HF. Succinates Of alkalis and most Ag, Hg, Pb, Cu, others, (Ba, Sr, Ca, Fe'", Sn. Al, Zn, Co, Fe", slightly). Sulphates Most sulphates, except Ca slightly. Basic Ba, Ca, Pb, Sr, Ba, Sr, Ca, Pb, and a sulphates of Hg, and anhydrous few basic ones (Ag. 2 SO 4 Fe*YBi,Sn*s61. Cr sulphates. si. sol.) in HC1. Sulphides Of alkalis, Ba, Sr, (Ca, Most are decom- Mg, si.). posed. Ag, As, Bi, Cu, Pb are sol. in HNO 3 ; Co, Hg', Hg", Ni, req. aq. regia Sulphites Of alkalis, (Ba, Sr, Ca, All others decom- acid sulphites). posed. Tartrates Of alkalis only. All sol. in acids. Thiocyanates Of alkalis, Ba, Sr, Ca, Bi, Cu, Hg" (Hg 7 Fe. si. in cone, acid, AgCNS sol. in cone. HNO 3 ). Thiosulphates Of alkalis, Ca, Sr, (Pb, All decomposed. Ag, Ba, slightly). APPENDIX 115 REAGENTS FOR QUALITATIVE ANALYSIS. All the solutions are equivalent solutions except where otherwise stated, and most of them are prepared by dissolving a gramme-equivalent of the re- agent in one litre of water. Name. Formula. Equivalent or gms. per litre. Preparation of Solutions. Strength. Acetic acid HC 2 H 3 0- 2 59'58 Glacial acetic acid. i77B > 5 5 > > j Diss. 294 c.c. of glacial E acetic acid in i litre of of aq. Citric acid H 3 C, ; H 5 7 I9O'62 350 grams. 5E > j j> > > Diss. 70 gms. in i litre. E Hydrochloric acid HC1 36-I8 Sp. gr. ri6i. zoE > > Sp. gr. 1-084. 5E j > > > > > Dilute 200 c.c. of 5E to E i litre. Hydrofluoric acid HF 19-9 Sp. gr. 1-15. I2'9E Nitric acid HN0 3 62-57 Sp. gr. 1-5 at 15-5 C. 2 3 E > > > Sp. gr. 1-42. i6E 5 > > > Sp. gr. 1-1656. ,, 5H > > > > Dilute 200 c.c. of 5E to E i litre. J > J > Oxalic acid H 2 C 2 4 44-67 Diss. 94-5 grams, of IE HAO 4 ,2H 2 Oinilitre. Sulphuric acid H 2 S0 4 48-67 Sp. gr. i. 8427 at 1 5 -5 C 36E > > > ) Sp. gr. 1-1527. 5E > > > > ) > Dilute 200 c.c. of 5Eto E i litre. Sulphurous acid H 2 S0 3 4073 Saturated sol. in aq. 37E > > Dilute 270 c.c. to i litre. E Tartaric acid H 2 C 4 H 4 6 74-46 Diss. 375gms. in i litre. 5E 75 E Tannic acid CuHioOg Diss 10 gms. in 100 c.c. of aq. Bromine Br 79'36 Br. sp. gr. 2.96. 37E Bromine water Br, aq. Saturated sol. in aq. iE Chlorine , , Cl, aq. 35'lS Saturated sol. ,, *E Hydrogen peroxide H 2 0. 2 16-88 10 vol. sol. ,, r8E Hydrogen sulphide SH 2 16*91 Saturated sol. ,, iE u6 APPENDIX Name. Formula. Equivalent or gms. per litre. Preparation of Solutions. Strength. Ammonium acetate Dil. "880 to sp. gr. 5H 9643- j > 200 c.c. of 5K, diluted E to i litre. , , oxalate (NH 4 ) 2 C 2 4 30-8 42-6 gms. (NH 4 )A0 4 , |H 2H 2 O in i litre. , , sulphate (NH 4 )- 2 S0 4 65-60 65*6 gms. in i litre of E aq. , , sulphide (NH 4 ) 2 S 33*84 Saturate 600 c.c. of E 5H NH 4 OH with SH 2 and add 400 c.c. of E. NH 4 OH. Barium chloride BaCl 2 103-38 122 gms. BaCl 2 ,2H 2 O E in i litre aq. Calcium ,, ' CaCl 2 55*o8 109-5 g ms - CaCl a ,6H s O E ,, hydroxide Ca(OH) 2 3678 A saturated solution = i in 600 aq. ,, sulphate CaS0 4 67*57 Saturated sol. sVE Copper sulphate CuS0 4 79-22 i24'75gms. CuS0 4 ,5H. 2 E in i litre. Ferrous sulphate FeS0 4 75-42 139 gms. FeSO 4 .7H 2 O. E Ferric chloride FeCl 3 53*68 18.67 gms. of Fe as E Fe 2 O 3 in 200 c.c. of 5E HC1 and dil. to i litre. For neutral FeCl 3 add Na 2 CO 3 to the FeCl 3 sol. until a ppt. just forms and then filter. Gold chloride AuCl 8 100-41 Dissolve 62 '5 gms. Au E in aqua regia, evap- orate excess of acid ". and dilute to i litre. APPKNDIX 117 Name. Formula. Kquivalent or gms. per litre. Preparation of Solutions. Strength. Lead acetate Pb2C 2 H 3 O, I6r25 189-5 gms. Pb2C 2 H 3 O 2 , E 3H 2 0. Magnesium s u 1 - MgS0 4 5975 i23'5gms. MgSO 4 ,7H 3 O. E phate Magnesia mixture 68 gms. MgCl 2 ,6H 2 in 500 c.c. aq., add 165 gms. NH 4 C1 and 300 c.c. of ENH 4 OH sol. and dilute to i litre. Mercurous nitrate HgNQa 260*07 56 gms. of HgNO 8 ,H 2 O JK dissolved in 40 c.c. 5E HNO 3 and diluted to i litre ; add a little Hg. Mercuric chloride HgCl 2 134-43 53-7 gms. HgCl 2 IE Platinum ,, PtCl 4 83'5o 155-86 gms. H 2 PtCl 6 in E i litre aq. Potassium bichro- K 2 Cr 2 O 7 I46'i4 146 gms. in i litre aq. E mate Potassium c h r o - K 2 CrO 4 96-47 96*5 gms. in i litre. E mate Potassium cyanide KCy 64-70 65 gms. E Potassium ferro- K 4 FeCy 6 91-49 io5'5gms K 4 FeCy 6 ,3H 2 O E cyanide Potassium ferri- K s FeCy G 109-4 109-5 gms. E cyanide Potassium hydrox- KOH 5574 280 gms. 5E ide > Potassium iodide KI 164*76 165 gms. 5E Potassium nitrite KNO 2 84'55 84-5 gms. E Potassium thiocy- KCyS 96-53 97 gms. in i litre. E anate Silver nitrate AgNOa 168*69 68'5 gms. E Sodium acetate NaC 2 H 8 O 2 81-46 540 gms. NaC 2 H 3 O 2 3H 2 O 4E in i litre. Sodium acetate and NaA + HA 250 c.c. 4E Na acetate E acetic acid and 200 c.c.i 7E acetic acid diluted to i litre. Sodium carbonate Na 2 C0 3 52-65 52 gms. (anhydrous). Sodium hydroxide NaOH 39-76 200 gms. 5E Sodium hypo- NaCIO 73-94 chlorite n8 APPENDIX Name. Formula. Equivalent or gms. per litre. Preparation of Solutions. Strength. Sodium nitroferri- cyanide Na 2 FeNOCy 5 Sodium phosphate Na..HPO 4 47 '05 119*3 g ms - Na 2 HPO 4 , I2H 2 O in i litre. E Sodium sulphate Na 2 SO 4 70-55 i6ogms. Na 2 SO 4 ioH 2 O in i litre. E Sodium thiosul- phate Stannous chloride Na 2 S 2 O 8 SnCl a 78-53 94'23 1 24 gms. Na 2 S 2 O 3 ,5H 2 O. Diss. ii2'5 gms. SnCl a , 2H 2 O in 200 c. c. of 5E HC1, dilute to i litre ; add a little tin. E E Strontium sulphate SrS0 4 91-14 Saturated solution. T**B Erdmann's reagent Fehling's solution Froehde's reagent Iodine in KI Mandolin's reagent Mayer's reagent Nessler's reagent Phenolphthalein SehifTs reagent Ammonium molybdate Cuprous chloride solution SPECIAL REAGENTS. Six drops cone. HNO ;5 in 100 c.c. of water added to 240 c.c. of cone. H 2 SO 4 . 6 '9 gms. CuSOi in 30 c.c. of water, i drop H 2 SO 4 , add 35 gms. Rochelle salt and 10 gms. NaOH in 50 c.c. water, make up to 100 c.c. Diss. i gm. am. molybdate in 100 c.c. cone. H 2 S0 4 . Diss. i gm. I and 2 gm. KI in 50 c.c. water. Warm '5 gm. vanadium chloride or oxide with 100 c.c. cone. H 2 SO 4 . 13-5 gms. HgCl 2 and 50 gms. KI in 940 c.c. of water. (i) 3-5 gms. KI in 10 c.c. H 2 O ; (2) r6 gms. HgCl 2 in 30 c.c. H 2 O ; (3) 3 gms. KOH in 60 c.c. HsQ. Pour (2) into (i) slowly, then add (3). i gm. phenolphthalein in 50 c.c. spirit, make up to 200 c.c. with water. To a pale sol. of fuchsine in water add SO 2 until decolourized. Diss. 10 gms. of the salt in 40 c.c. of ^E NH 4 OH, pour slowly into 120 c.c. cone. HNO 3 , cool the solution ; decant for use after settling some hours. Digest CuCl 2 with metallic Cu and HC1. APPENDIX 119 Indigo solution Litmus solution Litmus paper Turmeric paper Mix together i part of indigo powder and 4 of cone. H 2 SO 4 ; allow to stand a few days, then pour into 20 parts of water. Digest 10 gms. of powder with 250 c.c. of warm water for a few hours, decant the clear sol., add a few drops HNO 3 until a dis- tinct purple colour is obtained. Soak strips of porous paper in the above solution. i part turmeric root (powdered) digested in 6 of alcohol and filtered. Soak strips of porous paper in this solution. Borax Calcium carbonate Fusion mixture Mieroeosmie salt Soda-lime DRY REAGENTS. Na 2 B 4 O 7 ,ioH 2 O. Fused : Na. 2 B 4 O 7 . CaCO 3 . Use Iceland spar. 10 gms. Na 2 CO 3 and 13 gms. K 2 CO 3 . Na(NH 4 )HPO 4 .4H 2 O. Shake CaO with NaOH sol. and dry. INTERNATIONAL ATOMIC WEIGHTS. H == i. O = 16. Aluminium Al 26-9 27-1 Copper Antimony Sb 119-3 I20'2 Erbium ... . Argon A 39'6 39'9 Fluorine ... Arsenic As 74-4 75'o Gadolinium Barium Ba 136-4 i37'4 Gallium ... . Bismuth Bi 206*9 208*5 Germanium Boron B io'9 ii Glucinum Bromine Br 79-36 79-96 (Beryllium) Cadmium Cd in-6 112*4 Gold Caesium Cs 132 133 Helium ... Calcium Ca 39-8 40' i Hydrogen i Carbon C 11-91 12. OO Indium Cerium Ce 139 140 Iodine ... . Chlorine Cl 35'i8 35'45 Iridium ... Chromium Cr 51-7 52-1 Iron Cobalt Co 58-56 59'o Krypton ... . Columbium Cb 93'3 94 Lanthanum (Niobium) Lead ... . H = i. O - 16. Cu 63-1 63-6 E 164*8 166 F 18*9 19 Gd 155 156 Ga 69-5 70 Ge 71-9 72-5. Gl 9-03 9-1 Au 195-7 i97'2 He 4 4 H i "ooo i '008 In 113"! 114 I 125*90 126*85 Ir 191-5 i93' Fe 55'5 55*9 K 81-2 8r8 La 137-9 138-9 Pb 205-35 206*9 120 APPENDIX H- i = 16. H = i O = 1 6. lyithium Li 6*98 7-03 Selenium . . . ... Se 78-6 , 79'2 Magnesium Mg 24-18 24.36 Silicon ... Si 28-2 28*4 Manganese Mn 54-6 55-0 Silver ... Ag 107-12 107-93 Mercury Hg 198*5 200'0 Sodium ... Na 22-88 23'05 Molybdenum . . Mo 95-3 96-0 Strontium ... Sr 86-94 87-6 Neodymium . . . Ne 142-5 I43' 6 Sulphur . . . ... S 31-83 32-06 Neon 19-9 20 Tantalum... ... Ta i8r6 183 Nickel ... ... Ni 58-3 58-7 Tellurium ... Te 126*6 127*6 Nitrogen N 13-93 i4'<>4 Terbium ... ... Tb 158-8 1 60 Osmium Os 189*6 191 Thallium ... ... Tl 202-6 204-1 Oxygen O 15-88 1 6 -oo Thorium ... ... Th 230-8 232*5 Palladium Pd 105*7 IQ 6'5 Thulium ... ... Tmi69'7 171 Phosphorus P 30'77 3i'o Tin ... Sn nS'i 119*0 Platinum Pt 193-3 i94'8 Titanium ... ... Ti 477 48-1 Potassium . . K 38-86 39-15 Tungsten . . . ... W 182-6 184-0 Praseodymium. .. Pr 139-4 140-5 Uranium ... ... U 236-7 238-5 Radium Ra 223-3 225 Vanadium ... V 50-8 51*2 Rhodium Rh 102*2 103*0 Xenon ... X 127 128 Rubidium Rb 84-8 85-4 Ytterbium ... Yb 1717 173*0 Ruthenium Ru 100*9 ioi"7 Yttrium . . . ... Yt 88-3 89*0 Samarium Sm 148-9 150 Zinc ... Zn 64-9 65'4 Scandium Sc 43-8 44-1 Zirconium ... Zr 89-9 90*6 WEIGHTS AND MEASURES. The unit of length is i metre = 39*37079 inches, or 3*2809 feet, or 1*0936 yards. The unit of volume is i litre = *i x *i x 'i metre, i.e., i cubic deci- metre. The unit of weight is i gramme - wt. of i cubic centimetre (*oi m.) of water at 3*9 C. 15*4325 troy grains. Multiples of the above Kilo 1000. Hecto = 100. Deka 10. Fractions of the above Deci 0*1. Centi 0*01. Milli *ooi. 121 APPENDIX MEASURES OF LENGTH. i micron (/u.) *ooi m.m. "00003937 or roughly 1/25000 inch. i m.m. "03937 inch. i centimetre, c.m. 10 m.m. 394 inch. i metre 1000 m.m. 39*371 in- ches = 3*2809 feet. i kilometre == 1000 metres 1093 '6 yards = '621 Eng. mile. i inch 25*400 m.m. i inch 2*54 c.m. i foot =. '3048 metre. i yard = '9141 metre. i Eng. mile = 1*610 kilometres. WEIGHTS. i gram r : 15-432 grains =: "035 oz avoir. '032 oz. troy. i kilogram me or "kilo" = looogms- = 2*2046 Ibs., or 2-Jlbs. avoir, (approximately). Metric ton or 1000 kilos = 2204*62 Ibs. avoir. i grain '065 gram. i oz. avoir. = 28*349 grams. i oz. troy 480 grs. = 31 '1035 grams. i Ib. troy 373*24 grams, i Ib. avoir. = 453*584 grams, i cwt. = 50*0802 kilos. VOLUMES. i litre = 1000 c.c. = 61*027 cubic inches = 1*760 or i^ pints, or '220 gallon or 35*22 fluid ozs. i fluid oz. 28*349 c.c. i pint '5679 litre, i gall. = 4*54346 litres, i cubic inch ~ 16*39 c.c. i cubic foot 28*31531 litres. NOTES. To convert grams to grains = Log. grams -f 1*18843 = log. grains. To convert grains into grams log. grains + 2*81157 = log. grams. To convert Fah. degrees to centigrade, f ^-32). To convert Cent, degrees to Fah. ( C) + 32, or multiply the C by 2, sub- tract ^ and add 32, e.g., 16*2 x 2 - 3*24 + 32 61*26 F. i litre of dry H. at oC. and 760 m.m. (or Crith) == '0896 gram, i litre of dry air at oC and 760 m.m. pressure 1*2987 or 1*3 grams, i gram of H at oC and 760 m.m. pressure = 11*16 litres. Sp. gr. of air == 14*43. H. = i. Coefficient of expansion for gases = ^ F or 0*003665. Parts per 100,000 - grains per gall. -4- 0*7 Grains per gall. = grams per litre x 70. 122 AgNOs As,0 3 AuCla BaCl a BaCO 3 Ba(OH) 2 Br aq. CaCl 2 CaF, Ca(OH) 2 Ca 3 (P0 4 ) 2 CaSO 4 CHC1 3 CO, cs, Cl aq. Co2NO 3 CuO Cu(OH) 2 CuSO 4 Fed, FeSO 4 H 2 C 4 H 4 6 H 2 C 2 4 HC1 HF HNO 3 H 2 PtCl 6 H 2 SO 3 H 2 S0 4 H 2 2 HgCl 2 HgCy 2 Hg 2 N0 3 HgN0 3 KBr KBrO KC1 APPENDIX FORMULA OF REAGENTS. Silver nitrate. KC10 ,, hypochlorite. Arsenious oxide. KC1O 3 ,, chlorate. Gold chloride. K a CO* ,, carbonate. Barium chloride. K 2 Cr0 4 ,, chromate. Barium carbonate. K 2 Cr 2 7 ... . ,, bichromate. Barium hydroxide. KCy (KCN).. Potassium cyanide. Bromine water. KCNS KHSO 4 ,, thiocyanate. , , bisulphate. Calcium chloride. K 4 FeCy 6 ... ,, ferrocyanide. Calcium fluoride. K,FeCy ... ,, ferricyanide. Calcium hydroxide. KI ,, iodide. Calcium phosphate. KMnO 4 ,, permanganate. Calcium sulphate. KNO. 2 ,, nitrite. Chloroform. KN0 3 ,, nitrate. Carbon dioxide. KOH ,, hydroxide. Carbon bisulphide. MgCl 2 Magnesium chloride. Chlorine water. MgS0 4 Magnesium sulphate. Cobalt nitrate. MnO. Manganese dioxide. Cupric oxide. MnSO 4 Manganese sulphate. Cupric hydroxide. Na 3 AsO 3 ... Sodium arsenite. Cupric sulphate. Na 8 AsO 4 ... ,, arsenate. Ferric chloride. NaCIO ,, hypochlorite. Ferrous sulphate. Na 2 C0 3 ... ,, carbonate. Tartaric acid. Na 2 FeNOCy 5 ,, nitroprusside. Oxalic acid. NaHC0 3 ... , , bicarbonate. Hydrochloric acid. Na 2 HPO 4 ... ,, phosphate. Hydrofluoric acid. NaHSO s ... ,, bisulphite. Nitric acid. NaNO a , , nitrite. Chloroplatinic acid. NaOH ,, hydroxide. Sulphurous acid. Na 2 S ,, sulphide. Sulphuric acid. Na 2 SO 3 ... ,, sulphite. Hydrogen dioxide Na 2 S 2 O 3 ... ,, thiosulphate. (hydroxyl). NH 4 C1 Ammonium chloride. Mercuric chloride. (NH 4 ) 2 C 2 4 ... ,, oxalate. Mercuric cyanide. CNH 4 ) 2 C0 3 ... ,, carbonate. Mercuric nitrate. (NH 4 ) 2 Mo0 4 .. ,, molybdate. Mercurous nitrate. NH 4 OH ... ,, hydroxide. Potassium bromide. (NH 4 ) 3 P0 4 ... ,, phosphate. ,, hypobromite. NH 4 SH J| ,, hydrosulphide. , , chloride. NiSO 4 Nickel sulphate. Pb2C. 2 H 3 O, Lead acetate. Pb2NO 8 ... Lead nitrate. PbS ... Lead sulphide. PtCl 4 SH 2 . . . Platinum tetrachloride. ... Hydrogen sulphide. APPENDIX SO, SbCl 3 SnCI 2 SrCl 2 ZnCL 123 Sulphur dioxide. Antimony trichloride. Stannous chloride. Strontium chloride. Zinc chloride. INDEX. Page. Acids, inorganic, reactions ... 35 Acids, organic, reactions ... ... 44 Acids, preliminary tests for ... 101 Acids, preparation of solution ... 103 Acids, tables for detection of ... 104 Acetic acid ... ... 46, 112 Acetone ... ... ... 58 Acetaldehyde ... 57, m Acetanilide (Antifebrin) ... ... 77 Alcohol ... ... ... ... in Alcohols and derivatives ... ... 55 Alkalis, in silicates ... no Alkaloids, general precipitants ... 70 Alkaloids, detection of single ... 78 Alloys and Metals ... ... 91 Aluminium reactions ... ... 15 Ammonium reactions ... ... 21 Amyl alcohol ... ... ... 56 Amyloids ... ... ... 64 Aniline ... ... 68, 112 Antimony reactions ... ... 13 Antipyrine ... 77 Appendix ... ... ... in Aromatic series ... ... 50, 67 Arsenic Group, separation ... ... 95 Arsenic, reactions. . ... 12, 13 Atomic Weights, International, list of 119 Atropine ... ... ... 71 Barium Group, separation ... ... 99 Barium, reactions... ... ... 19 Bases, general table for Separation of 93 Bases, preparation of solution ... 90 Benzene ... 67, 112 Benzine ... 67 Benzoic acid ... ... 50,106 Beryllium reactions ... ... 28 Bismuth, reactions ... ... n Borax bead tests ... ... ... 86 Boric acid (Boracic acid) ... ... 41 British gum ... ... ... 64 Bromic acid ... 37 Brucine ... 72 Butyric acid ... 47 Cacodyl ... 46 Cadmium reactions ... ... 12 Caesium reactions ... ... 34 Caffeine ... ... ... 72 Calcium reactions ... ... 19 Cane sugar ... 61 Carbamide ... ... ... 60 Carbimide ... ... ... 44 Carbolic acid ... ... ... 67 Carbohydrates ... ... ... 61 Carbon, in C compounds ... ... in Carbon bisulphide ... 59, in Carbonic acid ... ... ... 43 Cellulose Cerium reactions Charcoal tests Chloral hydrate ... Chloric acid reactions Chloroform Page. ... 65 ... 28 85, 87, 88 57, in 36, 106, 107 58, in ,, test for impurities . . 58 Chromic acid reactions ... ... 16 Chromium reactions ... ... 16 Cinchonine ... ... ... 73 Citric acid ... ... ... 50 Closed tube tests ... ... 8285 Cobalt reactions ... ... ... 18 Cocaine ... ... ... 73 Codeine ... ... ... 73 Columbium reactions ... ... 23 Coniine ... ... ... 71 Copper reactions ... ... ... 11 Copper Group, separation ... ... 95 Cyanic acid ... ... ... 44 Daturine ... ... ... 71 Dextrin ... ... ... 64 Dextrose ... ... ... 61 Didymium ... ... ... 29 Digitalin ... ... ... 66 Double cyanides ... ... 44, no Elements in C compounds ... ... in Ether (Ethyl oxide) ... 56, 112 Ethyl alcohol ... ... 55, in Ethyl acetate ... ... ... 112 Examination for Acids ... ... 101 Examination for Bases ... ... 93 Film tests ... ... ... 89 Flame colour tests ... ... 86 Fluosilicic acid ... ... ... 41 Formalin ... ... ... 57 Formaldehyde ... ... 57 Formic acid ... ... 46,112 Formulae of Reagents ... ... 122 Gallium reactions ... ... 33 Gallic acid ... ... ... 51 Gallo-tannic acid ... ... ... 52 General Table for Bases ... ... 93 Glucinum reactions ... ... 28 Glucoses ... ... ... 61 Glucosides ... ... ... 66 Glycerol (Glycerin) 59, 112 Gold reactions ... ... 24 Grape sugar ... ... 61 Gum Arabic ... ...65 Halogens in C compounds. . ... in Hippuric acid ... ... ... 54 Hydriodic acid ... 37, 106 Hydrobromic acid . . 36, 106 Hydrochloric acid 35, 106 Hydrocyanic acid... ... 44, 106 124 INDEX 125 Page. Hydroferricyanic acid ... 45, 107 Hydro ferrocyanic acid ... 45, 107 Hydrofluoric acid ... ... 35 Hydrofluosilicic acid ... . . 41 Hydrogen sulphide ... . . 39 Hydrogen in C compounds ... in Hydroxyl (Hydrogen peroxide) ... 59 Hypochlorous acid ... 35, 107 Hypophosphorous acid ... 43 Indium, reactions ... ... 32 Inorganic acids ... ... 35 Insoluble substances ... ... 108 Inulin (starch) ... ... 64 lodic acid ... ... 37 Iridium reactions ... ... 25 Iron reactions ... ... ... 15 Iron Group, separation ... ... 96 Ketone .. .. ... ... 58 Lactic acid ... ... 50 Lactose . . ... ... 62 Laevulose ... ... 61 Lanthanum reactions ... ... 29 Lead reactions ... ... ... 9 Lithium reactions... ... ... 21 Magnesium reactions ... ... 20 Magnesium Group, separation ... 100 Malic acid ... ... 49 Maltose . . ... ... 62 Manganese reactions ... ... 17 Match tests ... ... 88 Meconic acid ... ... 53 Mercury reactions ... ... 10 Metaboric acid . . ..'. ... 41 Metals and Alloys ... ... 91 Metaphosphoric acid ... ... 43 Methyl alcohol ... ... 55 Milk sugar ... ... 62 Molybdenum reactions ... ... 25 Morphine ... ... 74 Narcotine ... ... ... 74 Nickel Group, separation ... ... 98 Nickel, reactions ... ... 17 Nicotine ... ... 71 Niobium reactions ... ... 23 Nitric acid ... ... 40 Nitro benzene . . ... ... 112 Nitrogen, in C compounds ... in Nitroprusside of Sodium ... ... 40 Nitrous acid ... ... 40 Non-volatile solid alkaloids ... 71 Organic acids, reactions ... ... 44 Organic liquids, tests for ... ... in Osazones ... ... ... 63 Osmium reactions ... ... 23 Oxalic acid ... ... ... 47 Palladium reactions ... ... 23 Papaverine ... ... ... 75 Paraffin oils ... ... ... 112 Perchloric acid reactions ... ... 36 Peroxide of Hydrogen ... ... 59 Phenacetin ... ... ... 77 Phenazone ... ... ... 77 Phenol ... ... ... ... 67 Phenylamine ... ... ... 68 Phenyl hydrazin, reaction for sugars 63 Page. Phosphates Table, separation ... 97 Phosphoric acid (ortho) ... ... 42 Phosphorous acid ... ... 43 Phosphorus in C compounds ... in Platinum reactions ... ... 25 Potassium, reactions ... ... 20 Preliminary Tests for Acids ... 101 Preliminary Tests for Bases 81 90 Preparation of the Solution ... 90 Propionic acid ... ... 47 Prussian blue ... ... 45 Pyridine ... ... ... ... 68 Pyroboric acid reactions ... ... 41 Pyrogallol (pyrogallic acid) ... 52 Pyrophosphoric acid ... ... 43 Qualitative Analysis Tables 81 Quinine ... ... ... 75 Quinoline ... ... ... 69 Rarer Metals of Group I ... ... 21 HB ... 24 HI ... 28 ., IV ... 31 VI ... 34 Reagents Liebermann's ... 67 ,, Preparation of ordinary... 115 ,, ,, special ... 118 ,, Dry ... ... ... 119 ,, Formulae of ... ... 122 Rubidium ... ... ... 34 Saccharose (Sucrose) ... ... 61 Salicin ... ... ... ... 66 Salicylic acid ... ... ... 51 Selenium reactions ... ... 26 Separation of Au from Pt ... ... 25 BeO from A1 2 O 3 ... 28 Li in waters... ... 21 Mo in minerals ... 26 Ni from Co ... ... 18 Te 27 U in minerals ... 32 Silica and Silicates ... ... 41 Silicic acid ... ... ... 41 Silicofluoric acid ... ... ... 41 Silver, reactions ... ... ... 9 Silver Group, separation ... ... 94 Sodium reactions ... ... ... 20 Sodium nitroprusside, preparation ... 40 Solubilities, Table of ... ... 112 Solution, preparation of, for analysis 90 Spirit of Wine ... ... ... 55 Starch ... ... ... ... 64 Strontium reactions ... ... 19 Strychnine ... ... ... 76 Succinic acid ... ... 49, 106 Sugar, summary of reactions ... 63 Sulphine (sulphuretted hydrogen) 39 ,107 Sulphocyanic acid... ... ... 46 Sulphur in C compounds ... ... in Sulphuric acid ... ... 38, 107 Sulphurous acid ... ... 38, 107 Table of Solubilities ... ... 112 Tannic acid ... ... ... 52 Tannin ... ... ... ... 52 Tantalum, reactions ... ... 31 Tartaric, distinction from Citric, acid 49 126 INDEX Tartaric acid Table I Separation of Bases II III IIlA IV V ... VI ... Tellurium reactions Thallium reactions Theine Thiocyanic acid Thiosulphuric acid Thorium reactions Tin reactions Titanium reactions Page. . 48 94 95 , 96 9 ... 99 ... loo ... 27 ... 22 ... 72 46, 107 39, io? ... 30 ... 14 ... 30 Tungsten reactions Turnbull'sblue Turpentine Uranium, reactions Urea Uric acid ... Vanadium, reactions Vera trine Volatile bases Volatile liquid alkaloids Weights, atomic ... Weights and Measures Wolfram, reactions Wood spirit Zinc, reactions Zirconium, reactions Page. . 21 45 . 112 31 . 60 53 34 . 76 . 68 120 21 55 17 29 CALIFOIT" 14 DAY USE RETURN TO DESK FROM WHICH BORROWED LOAN DEPT. This book is due on the last date stamped below, or on the date to which renewed. Renewed books are subject to immediate recall. MAY 1 A 6/ 6PM Je? , rtVi 1 CLl . 8? .> Jus) JAN 281970 85 ar?o .CD. JANI A 70-8PH Mi ^fl 9197U7- A if f 1 ' REC'DLD MAR 1 71-9AM 1 General Library LD 2lA-60m-2,'67 University of California (H241slO)476B Berkeley GW lib. J967 LIBRARY USE RETURN TO DESK FROM WHICH BORROWED LOAN DEPT. LD 62A-50m-7,'65 (F5756slO)9412A .General Library University of California Berkeley .1, ? .J