UC-NRLF EXCHANGE The Conductivity, Temperature Coefficients of Conductivity, and Dissociation of Cer- tain Electrolytes in Aqueous Solution from to 35. Probable Induc- tive Action in Solution, and Evidence for the Com- plexity of the Ion* DISSERTATION SUBMITTED TO THE BOARD OF UNIVERSITY STUDIES OF THE JOHNS HOPKINS UNIVERSITY IN CONFORMITY WITH THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY BY LULA GAINES WINSTON, BALTIMORE June, 3911 EASTON, PA.: ESCHBNBACH PRINTING Co. 1911 The Conductivity, Temperature Coefficients of Conductivity, and Dissociation of Cer- tain Electrolytes in Aqueous Solution from to 35. Probable Induc- tive Action in Solution, and Evidence for the Com- plexity of the Ion. DISSERTATION SUBMITTED TO THE BOARD OF UNIVERSITY STUDIES OF THE JOHNS HOPKINS UNIVERSITY IN CONFORMITY WITH THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY BY LULA GAINES WINSTON \ \ BALTIMORE June, 1911 EASTON, PA.: PRINTING Co. 1911 CONTENTS. Page. Introduction 5 Historical 5 Experimental 12 Solutions 12 Water 12 Discussion of Results 13 Ammonium Nitrate 14 Ammonium Sulphate 15 Acid Ammonium Sulphate 15 Sodium Sulphate 16 Borax 17 Potassium Acetate 18 Potassium Permanganate 18 Di-Potassium Phosphate 19 Strontium Acetate 21 Magnesium Bromide 22 Magnesium Nitrate 22 Magnesium Formate 23 Magnesium Acetate 24 Cadmium Chloride 25 Cadmium Bromide 26 Cadmium Iodide 27 Lead Chloride 28 Aluminium Chloride 29 Aluminium Nitrate 30 Aluminium Sulphate 31 Chromium Chloride 31 Chromium Sulphate 32 Manganous Sulphate 34 Silver Nitrate 35 Cobalt Bromide 35 Copper Sulphate 36 Uranyl Chloride 38 Uranyl Nitrate 39 Uranyl Sulphate 39 Uranyl Acetate 40 Figures 41 Summary 48 Biography 50 251837 ACKNOWLEDGMENT. The author wishes to take this opportunity to express her gratitude to President Remsen, Professors Morse, Jones , and Renouf , Associate Professor Acree, and Dr. Reid for valuable instruction and advice. Special thanks are due Professor Jones, at whose suggestion and tinder whose guidance this investigation was carried out. The author would also gratefully acknowledge assistance received from Professors Ames and Whitehead, of the Depart- ment of Physics. The Conductivity, Temperature Coefficients of Con- ductivity and Dissociation of Certain Electro- lytes in Aqueous Solution from to 35* Probable Inductive Action in Solu- tion, and Evidence for the Complexity of the Ion* INTRODUCTION This paper forms one of a series dealing with the conduc- tivity of electrolytes in aqueous solution. In it we shall take up for consideration the conductivity, temperature coefficients of conductivity, and percentage dissociation of certain salts, and shall show how these results confirm those already ob- tained, and point out some new relations. The work is part of an investigation which has been carried on in this labora- tory for a dozen years or more. The importance of such an investigation is obvious, since chemistry is a branch of the science of solutions, and one of the very best methods of study- ing solutions is the conductivity method. HISTORICAL Electrochemical theories were advanced as early as 1807 by Davy and by Berzelius. Berzelius was among the first to call attention to the electrically charged atom. Faraday appeared later, giving to the world the laws which bear his name. His work has stood the test of time. His law show- ing the relation between the quantity of electricity and amount of decomposition holds rigidly to-day, and in the light of the electron theory takes on a new meaning. In the years 1853 to 1859 Hittorf determined the relative velocities of the ions of many salts. He pointed out a relation between chemical activity and conductivity, and also called attention to the analogy existing between solutions and gases. This latter problem was taken up later by Raoult, Ostwald, van't Hoff, and others. The laws of Raoult, dealing with the lowering of the freezing point and vapor pressure of liquids, and Ostwald 's dilution law are well known. Van't Hoff, in 1887, working on osmotic pressure, found certain solutions that behaved ab- normally. Arrhenius, attempting to explain their behavior, pointed out the fact that salts and analogous substances break down into ions. Thus was given to the world the theory of electrolytic dissociation. Its truth is attested on every hand. Facts once inexplicable become wonderfully clear and lend confirmation to the theory. Many workers have appeared in the field since Arrhenius. The most important of these, perhaps, is Sir J. J. Thomson, whose brilliant experi- ments have well-nigh revolutionized our conception of matter. The result of the work already done may be summarized briefly as follows: The conductivity of electrolytes in solu- tion is dependent primarily on two things, viz., the number of ions and their velocity. These two factors may be affected by various others. The most important of these is tempera- ture. The effect of rise in temperature is chiefly to increase the velocity of the ions. The number of ions would not be greatly affected unless they were complex. In addition to the effect of temperature on the number and velocity of ions in solu- tion, there are still other factors which, for convenience, may be divided into three classes : 1 . Those dependent upon the solute. 2. Those dependent upon the solvent. 3. Those dependent upon the combination of the solvent with the solute. In class i factors dependent upon the solute mention should be made first of all of the effect of valence. This would determine largely the number of ions capable of entering into solution. As is well known, the conductivities of binary, ternary and quaternary compounds are found to vary con- siderably. Factors affecting the velocity of the ion would be the atomic weights and atomic volumes of the elements ex- isting in the compound. We would naturally expect that the velocity would be an inverse function of the atomic weight and atomic volume. Experimentally, however, this has not been found to be true. Jones and Pearce 1 found that those 1 Am. Chem. J., 38, 737 (1907). elements which have the smallest atomic volumes have the greatest hydrating power. This would tend to diminish their velocity. As to the factors dependent upon the solvent, the most im- portant are its viscosity, its dielectric constant and its asso- ciation. In class 3 should be placed the concentration of the solu- tion and the power of the solute and solvent to form solvates with one another. The conductivity of solutions has been studied from each of these standpoints, and much valuable data have been ac- cumulated. The effect of temperature has been worked out carefully by Jones and his coworkers, West, 1 Jacobson, 2 Clover, 3 West, 4 White, 5 Wightman, 8 and Hosford. 7 Conductivity always increases with rise in temperature from o to 65, while dis- sociation usually decreases slightly. The decrease in disso- ciation would tend to diminish the number of ions, and thus to lessen the conductivity, but this effect is more than offset by the increased velocity of the ions due to rise in tempera- ture. This decrease in dissociation may be accounted for in two ways. It may be due to a decrease in the association of the solvent, which would tend to decrease the dissociation of the dissolved substance; or it may be due to the fact that a rise in temperature diminishes the dielectric constant of the solvent and consequently its dissociating power, since, accord- ing to the Thompson-Nernst hypothesis, a substance having a high dielectric constant has great dissociating power. While, as just shown, the effect of temperature is to diminish the number of ions present, its effect on the velocity of ions is just the reverse. Rise in temperature increases the velocity of ions in two ways: First, it diminishes the viscosity of the solvent. Second, rise in temperature would decrease the 1 Am. Chem. J., 34, 357 (1905). 2 Ibid., 40, 355 (1908). 3 Ibid., 43, 187 (1910). *Ibid., 44, 508 (1910). s/itd.,44, 159 (1910). 6 /&*., 46, 56 (1911). 7 Ibid., 46, 240 (1911). 8 complexity of the hydrates formed. This also would tend to increase the velocity of the ions. At all events, the de- crease in the number of ions seems to be more than compen- sated for by the increase in their velocity, and the general effect of rise in temperature is, therefore, to increase the con- ductivity. The most important factor in its effect on conductivity with rise in temperature is hydration. That the dissolved substance combines with some of the solvent to form solvates seems now to be an undisputed fact, the existence of hydrates in solution being shown by several independent lines of evi- dence. 1 The close connection between hydration and water of crystallization has also been established in this laboratory. Important relations between amount of hydration and temperature coefficients of conductivity have been pointed out. Jones and his coworkers, Bingham, McMaster, Rouil- ler, 2 Veazey, 3 Guy, 4 Davis, Reinhart, Mahin, 5 Schmidt, 6 and Kreider 7 have made important observations on the effect of viscosity on the conductivity of electrolytes. The work in this laboratory has been extended to non- aqueous solutions. Apparatus has been improved, the range of temperature has been extended, old sources of error have been eliminated, and the conductivities of hundreds of com- pounds have been added to those already measured. The problem has been undertaken in this laboratory of measuring the conductivity of all of the more common acids, bases and salts in aqueous solution, from o to 65, and of calculating the dissociation whenever possible. This work will be pushed forward as rapidly and carefully as possible. One fact, overlooked thus far in the consideration of the conductivity of electrolytes, is the probable inductive action 8 1 Publication No. 60 of the Carnegie Institution of Washington. 2 Publication No. 80 of the Carnegie Institution of Washington. 3 Am. Chem. J., 41, 433 (1909). *Ibid. 46, 131 (1911). * Ibid. 7 Ibid. *Ibid. 41, 433 (1909). 42, 37 (1909). 45, 282 (1911). 45, 547 (1911). of the ion on the unionized molecule. In the solution of a salt there is every condition necessary for inductive action. There are the charged ions, the neutral molecules and the dielectric or solvent. Ordinary electrical induction in con- ductors, as is well known, takes place as follows: A charged body brought near to a neutral body, but separated from it by a dielectric, causes a separation of the electricity in the neutral body, drawing the opposite kind nearest to itself and repelling the like charge to the side farthest from itself. If, while the charged body is still near, the repelled charge in the conductor is removed by contact with some other body, on the removal of the charged body the once neutral body would be left charged with the opposite kind of electricity. The ion, a charged body, acting through the water (a dielectric) on an unionized molecule, would produce just such an effect. Several results may follow from this. First, a positive ion brought near to a neutral molecule, but separated from it by the nonconducting water, would cause a separation of the electricity in the molecule; the negative will be drawn near to the ion and the positive repelled. Suppose, for instance, that the repelled charge is not removed, the charged ion would simply attach itself to the molecule, and as a charged system move through the solution. Moreover, this charged system could play the part of the original ion and, acting through the water, in a similar way draw other molecules to itself. There would be a limit, of course, to the number of molecules which could thus be attached. This, no doubt, would be a function of the valency of the ion. If, on the other hand, the repelled charge is removed and the inducing ion then moves off, the once neutral molecule would be left charged with a sign opposite to that on the in- ducing ion, and moving through the solution would be able to attract other molecules or oppositely charged ions to itself. This, of course, would give rise to a great complexity of ions and molecules. The velocity of the ions would thus be greatly affected, because their masses would be greatly increased. This may in a measure account for the apparent discrepancy between the dissociation as found by the freezing point method 10 and that found by conductivity, since by this inductive ac- tion there would be brought about a change in the number of particles which would probably affect the dissociation as found by the freezing point method. The effect on conductivity, on the other hand, would be due rather to a change in the velocity of the ions. The com- plex ions would tend to move more slowly than the individual ion, thus making the conductivity measurements of dissocia- tion too low. The change in the number of particles would not be so apparent in the case of conductivity because, when, by means of induction, an ion attaches itself to a neutral molecule, it would still give rise to a charged system, and would not thereby reduce the number of charged particles in solution. The breaking up of these moving systems by heat would show itself in increased temperature coefficients. Jones and Pearce 1 have shown that the dissociation as measured by the conductivity method is less than that cal- culated from the freezing point lowering. Conditions were chosen such that the number of ions, velocity of ions, hydra- tion and viscosity were the same in both cases. It was found by them that the greater the dilution, the greater the differ- ence in dissociation as measured by the two methods. This is due to the fact that the complexity of the hydrate is greater, the greater the dilution. Evidence seems to be accumulating in many directions that the ions in solution are complex. Some interesting re- lations are brought out in connection with the various dilu- tion laws, to which sufficient attention has not as yet been directed, which apparently point to the complexity of mole- cules in solution. Ostwald's law, has been found to apply to weakly dissociated electrolytes, but not at all to strong electrolytes. Moreover, various dilu- tion laws have been formulated which apply to strong elec- trolytes but are extremely unsatisfactory when it is attempted to apply them to weaker electrolytes. 1 Am. Chem. J., 38, 743 (1907). II The question naturally arises, why this difference? The thought has suggested itself that it may be due to the com- plexity of the molecule one dilution law applying to solu- tions containing molecules of a certain complexity, while an- other would apply to solutions containing molecules of a different order of complexity. Of the many dilution laws for strong electrolytes only two will be considered, viz., that of Rudolphi and that of Van't Hoff. The Rudolphi formula is (i ct)VF Van't Hoff's is (i afV Since the Ostwald law, a' = K = K (i a)V applies to weakly dissociated electrolytes, in solutions to which it applies there are very few ions. If the Rudolphi formula is applied to a solution, a certain volume, V lt is obtained, corresponding to a definite value for a and for K. If now, retaining the same values as before for a and for K, the Ost- wald formula is applied to the same solution, there is obtained a volume V which is the square root of the volume obtained by the Rudolphi formula. In other words, there is found the relation ^V 1 /V = i, a relation which would indicate complexity of the molecule in solutions to which the Rudolphi formula applies. Treating the Van't Hoff formula in the same way, i. e., comparing the volume obtained by the use of the Van't Hoff formula with a certain solution, for a definite value of a and of K, with the volume obtained by the use of the Ostwald formula for the same solution, keeping a and K the same as before, there is found the relation V^ i a V^ a where V represents the volume when the Ostwald law was applied and V 1 the volume obtained when the Van't Hoff law was used. Now if V/ V = constant, the molecular weight would be the same in each case ; but on examining the formula it is 12 readily seen that the relation is not a constant one, but that it is a function of the dissociation. This would indicate complexity of the molecule in solutions to which the van't Hoff law applies. The interesting fact about this last relation is that the degree of complexity varies with the dissociation, i. e., with the number of ions present; just exactly what has been referred to above as the probable result of inductive action. Let us now turn to the consideration of the data in hand. EXPERIMENTAL The well known Kohlrausch method was used to deter- mine the conductivities. A Kohlrausch slide wire bridge was employed with an induction coil and telephone receiver. The cells used were of the type designed by Jones and Bing- ham. 1 The cell constants were redetermined at regular, short intervals. The measurements were made at o, 12. 5, 25, and 35. Three separate readings were taken for each solution at each temperature, different resistances being used for each reading. The average of the conductivities obtained by using each of these readings was taken to be the correct conductivity. The flasks and burettes were carefully calibrated at 20 by the method of Morse and Blalock. 2 Solutions Kahlbaum's "chemically pure" materials were taken as the starting point in almost every case. These were purified, whenever practicable, by crystallization. A solution some- what more concentrated than the most concentrated solution to be used was made up. Its strength was determined by volumetric or gravimetric methods, and the solutions pre- pared from it as a mother solution. This solution was made by direct weighing whenever it was possible, and in the measurements given below this method was always used un- less otherwise stated. Water The water used in making the solutions was prepared ac- 1 Am. Chem. J., 34, 493 (1903). 2 Ibid., 16, 479 (1894). cording to the method of Jones and Mackay, 1 which has been employed in this laboratory for many years. This method is too well known to need discussion here. The water thus ob- tained had a conductivity of about 0.9 to 1.3 X io~ 6 at o. Discussion of Results The following salts have been classified, approximately, according to the position of the metal in the Periodic System. The ammonium, sodium and potassium compounds would, therefore, be first in order. These are, therefore, grouped to- gether for consideration. A careful examination of the re- sults for these compounds will show some points of interest. (i) The difference in the conductivities of the binary, ternary and quaternary salts is quite evident. The conduc- tivity of ammonium nitrate, potassium acetate, and potas- sium permanganate, between o and 35, ranges from 46 at o, in the most concentrated solution of potassium acetate, to 163.62 at 35 in the most dilute solution of ammonium nitrate. The conductivity of those compounds which are not binary, viz., ammonium sulphate, acid ammonium sul- phate, dipotassium phosphate, sodium sulphate, and borax, at 35 in the most dilute solutions is, in every case, above 200, and for acid ammonium sulphate is considerably above 500. The very high values for the temperature coefficients of conductivity, expressed in conductivity units, in the case of the four sulphates is very noticeable. The highest values are 5, 6, and 7+ in the case of sodium sulphate, ammonium sulphate and acid ammonium sulphate, respectively; while for the other salts under consideration in this group, the temperature coefficient in conductivity units is 4 + . This is probably due to the fact that sulphates show a tendency towards polymerization. The very largest temperature coefficient of conductivity of this group belongs to acid ammonium sulphate. It is 7.96. This is doubtless accounted for by the fact that this salt breaks up into very complex ions. In the case of potassium acetate and potassium perman- 1 Am. Chem. J., 19, 91 (1897). ganate, it is somewhat peculiar that the temperature coeffi- cients of conductivity in per cent, are in both cases, from o through 25 , larger than those measured in conductivity units. It is also striking that in the case of acid ammonium sul- phate the temperature coefficients of conductivity decrease with rise in temperature. In dealing with the following data the percentage dissocia- tion is not discussed for the individual salts, but by means of curves which are given after the data their points of differ- ence are brought out. Ammonium Nitrate Table I Conductivity V 2 58.44 12. 5 78.92 25 101.51 35 119.48 8 64-35 84.25 H3.38 135.07 32 68.81 94-30 I23-I3 H6.53 128 71.64 98.45 128.44 152.92 512 73-63 101.39 132.64 157.48 1024 74.69 102.51 134-43 159-44 2048 75-25 103-39 134.79 160.39 4096 76.37 105.51 137.87 163.62 Table II Temperature Coefficients 0-12.5 12. 5-25 25-35< Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 2 I .64 2.8l 1.81 2 .29 I. 80 1.77 8 i-59 2.47 2-33 2.77 2.17 I.9I 32 2.04 2.97 2.31 2-45 2-34 1.90 128 2-15 3.0 2 .40 2-44 2.45 I.9I 512 2.22 3.02 2.50 2.47 2.48 1.86 1024 2.23 2-99 2-55 2-49 2.50 1.86 2048 2.25 2-99 2.52 2-44 2.56 1.90 4096 2-33 3.05 2-59 2.46 2.58 1.87 Table III Percentage Dissociation V 12. 5 25 35 2 76.5 74.8 73.6 73.0 8 84.2 79.9 82.2 82.6 32 90.1 89.4 89.3 90.0 128 93.8 93.3 ,93.2 93.5 512 96.4 96.1 96.2 96.3 1024 97.8 97.2 97.5 97.5 2048 98.5 98.0 97.8 98.0 4096 loo. o zoo. o 100.0 ioo. o Ammonium Sulphate Table IV Conductivity V 12. 5 25 35 2 82.37 112 .09 I45-09 170.72 8 98.06 136.28 179-57 213.19 32 115.27 160.26 210.98 254-86 128 I30-95 182.65 241.38 291 .69 512 139.69 195-77 259.21 313.00 1024 143 . 84 202.31 267.62 322.55 2048 150.62 209 . 74 275.96 337-47 4096 150.44 211-55 280.82 340.32 Table V Temperature Coefficients 0-12.5 12. 5-25 25-35< Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 2 2.38 2.89 2.64 2. 3 6 2.56 1.76 8 3.06 3.12 3-46 2-54 3.36 1.8 7 32 3.60 3.12 4.06 2-53 4-39 2.08 128 4.14 3-16 4.70 2-57 5-03 2.08 512 4-49 3.21 5.08 2.60 5.38 2.08 1024 4.68 3-25 5.22 2.58 5-49 2.05 2048 4-73 3-H 5-30 2-53 6.15 2.23 4096 4.89 3-25 5-54 2.58 5-95 2. 12. Table VI Percentage Dissociation 12. 5 25 35' 54.6 52.9 51.6 50.1 8 65.0 64.4 63-9 62.6 32 76.5 75-7 75-i 74-8 128 86.9 86.3 85-9 85-7 512 92.7 92.5 92.3 91.9 1024 95-4 95-6 95-2 94-7 2048 100. 99.1 98.2 99.1 4096 99.8 ioo. o loo. o ioo. o Acid Ammonium Sulphate Table VII Conductivity V 12. 5 25 35 2 155.26 186.49 2 i i . 99 226.O6 8 183.40 223.84 258.00 277.18 32 223.58 279-55 322.68 349-24 128 265.24 339.00 404.14 444.74 512 289.79 378.25 463 . 20 522.24 1024 295.22 386.88 483.5I 547-05 2048 303.41 4OO.OI 496.86 573.46 4096 304-26 401 . 96 497.11 576.66 i6 Table VIII Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units. cent. 2 2.50 1.61 2.04 1.0 9 I.4I 0.66 8 4.04 2.20 2-73 I .22 I.9I 0.74 32 4-48 2.OO 3-45 1.23 2.66 0.82 128 5.90 2 .22 5-21 i-54 4.06 i .01 512 7-08 2.44 6.79 1. 80 5-90 1.27 1024 7-33 2.48 7-73 2.00 6-35 i-3i 2048 7-73 2-55 7-74 1.94 7.66 i-54 4096 7.81 2-57 7.61 1.89 7.96 i .60 Table IX Percentage Dissociation V 12. 5 25 35 2 51.0 46.4 42.7 39.2 8 32 128 512 1024 2048 4096 ioo. o ioo. o loo. o loo. o Sodium Sulphate Table X Conductivity V 12. 5 25 35 60.3 55-7 5i-9 48.1 73-5 69.6 65.0 60.6 87.1 84.4 81.3 77.1 95-2 94.2 93-2 90.5 97.0 96.3 97-4 94-9 99-7 99 6 99-9 99-4 4 68.49 97-54 129.13 156.71 8 78.51 i i i . 46 146.40 178.24 32 94-51 132.72 176.76 215.19 128 107-54 152.49 203 . 10 247.02 512 117.46 166.24 221 .21 269.50 1024 119.65 169.61 226.34 276.92 2048 125-95 176.08 235-35 287.02 4096 127.73 181.61 243.42 294.48 Table XI Temperature Coefficients 0-12.5 12. 5-25 25-3S 9 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 2.32 3-39 2-53 2-59 2.76 2.14 8 2.63 3-35 2.80 2-51 3-i8 2.17 32 3-05 3-23 3-52 2.65 3-84 2.17 128 3.59 3-34 4-05 2.66 4-39 2.16 512 3-90 3-32 4.40 2.65 4-83 2.18 1024 4-00 3-34 4-54 2.68 5.06 2.19 2048 4-OI 3-i8 4-74 2.69 5-17 2.20 4096 4-31 3-37 4-94 2.72 5-n 2.10 17 Table XII Percentage Dissociation V 12. 5 25 35 4 53-6 53-7 53- i 53-2 8 61.4 61.4 60. i 60.5 32 73-9 73-i 72.6 73.0 128 84.1 84.0 83.4 83.9 512 91.9 91.6 90.9 91.5 1024 93.6 93.4 93.0 94.0 2048 98.5 97.0 96.7 97.4 4096 100.0 100.0 100.0 loo.o Borax Table XIII Conductivity V 12. 5 25 35 16 57-99 83.76 113-54 139-83 32 64.36 92.74 125.49 154-61 128 72.87 104.81 141.72 174-52 512 78.04 112.22 152.00 187.97 1024 79.20 II3-29 153-4 189.37 2048 83.45 119-55 I6I.23 198.31 4096 85.50 122.28 163.99 202:65 Table XIV Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 16 2.06 3.55 2.38 2.84 2.63 2.32 32 2.27 3.53 2.62 2.83 2.91 2.32 128 2.56 3.51 2.95 2.82 3.28 2.32 512 2.73 3.50 3.18 2.83 3.60 2.37 1024 2.73 3.45 3.21 2.83 3.60 2.35 2048 2.89 3.46 3.33 2.79 3.71 2.30^ 4096 2.94 3.44 3.34 2.73 3.87 2.36 Table XV Percentage Dissociation V 12. 5 25 35 16 67.8 68.5 69.2 69.0 32 75-3 75-8 76.5 76.3 128 85.3 85.7 86.4 86.1 512 91.3 91.8 92.7 92.7 1024 92.7 92.6 93.5 93.4 2048 97.6 97.8 98.3 97.8 4096 100.0 100.0 loo.o 100.0 i8 Potassium Acetate Table XV IConductivity V 12. 5 25 35 4 46-13 62.62 83-35 99.88 8 48.60 67. II 88.43 105.87 32 53-09 73-59 97.29 117.46 128 55-57 77-43 102.13 123.03 512 57-17 79.91 I05.I6 126.87 1024 58.33 81.14 106 . 84 I29.O9 2048 59.24 82.09 108.43 129.84 4096 59.06 81.89 108.65 129.90 Table XVII Temperature Coefficients 0-12.5 12. 5-25 25-35' Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 32 2.86 1.66 2.64 1.65 I. 9 8 8 .48 3-05 1.71 2-55 i-74 i 97 32 -1 .64 3-09 i .90 2.58 2.02 2.07 128 3 75 3-15 1.98 2-54 2.09 2.05 512 .82 3-17 2.02 2-53 2.17 2.06 1024 -83 3-14 2.06 2-54 2.23 2.09 2048 -83 3 09 2. II 2-57 2.14 i-97 4096 -83 3.10 2.14 2.61 2.13 1.96 Table XVIII Percentage Dissociation V 12. 5 25 35 4 77-8 76.3 76.6 76.9 8 82.0 81.8 81-3 81.5 32 89.6 89.7 89-5 90.4 128 93-7 94 4 93-9 94-7 512 96.4 97-4 96.7 97.6 1024 98.4 98.9 98.3 99 3 2048 100. 100. 99-7 99-9 4096 99 -6 99-8 100. 100. O Potassium Permanganate The strength of the mother solution was determined volu- metrically by means of potassium tetroxalate. 19 Table XIX Conductivity V 12. 5 25 35 8 59-34 8o.i7 104 . 36 124.74 32 63-75 87-13 113.70 136.05 128 66.76 91-38 119.31 142.42 512 66.46 91.14 117.90 141.49 1024 64.65 89-05 113-95 137.09 2048 63.72 86. 6i 110.80 133.02 4096 62.64 87.94 I I I . 8O 133-97 Table XX Temperature Coefficients 0-12.5 12. 5-25 25-35' Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 8 .67 2.8l 1.94 2.42 2.O4 I. 9 6 32 -87 2-93 2.13 2-45 2.24 1.97 128 97 2-95 2.23 2.44 2.31 1.94 5 12 97 2.96 2.14 2-35 2.36 2.OO 1024 95 3.02 1.99 2.24 2.31 2.03 2048 83 2.8 7 1.94 2.2 4 2.22 2.0O 4096 j >.O2 3-23 I.9I 2.17 2.22 1.99 Table XXI Percentage Dissociation V 8 88.8 12. 5 87.7 25 87-5 35 87.6 32 95-4 95-3 95-3 95-5 128 IOO.O IOO.O IOO.O IOO.O 512 99-5 99-7 98.8 99-4 1024 96.8 97-4 95-5 96.3 2048 95-4 94-8 92.9 93-4 4096 93-8 96.2 93-7 94.1 Dipotassium Phosphate This salt was precipitated by magnesia mixture and the phosphoric acid thus determined. Table XXII Conductivity V 12. 5 25 35 2 63.01 86.82 II3.04 138.16 8 79.19 109.25 143-34 174.91 32 91.69 127.42 l67.6l 203 . 80 128 102.47 H2.37 188.10 230.71 512 107.76 150.85 199.40 239.84 1024 109.35 152.23 200.52 242.65 2048 110.47 I57.04 206.13 242.54 4096 107. 16 I54-98 2OI .98 250.78 20 Table XXIII Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per units cent. units cent. units cent. I.9I 3-03 2. 10 2.42 2.51 2.22 2.4O 3-03 2-73 2.50 3.l6 2.21 2.86 3-05 3.22 2.53 3.62 2.16 3-19 3-n 3-66 2.57 4.26 2.27 3-45 3-20 3.88 2.57 4.04 2.03 3-43 3-14 3-86 2.54 4.21 2.10 3-73 3.38 3-93 2.50 3.64 1.77 3-83 3-57 3-76 2.43 4.88 2.42 Table XXIV Percentage Dissociation r 12. 5 25 35 57-o 55-3 54-8 55-i 7i-7 69.6 69.5 69.8 83.0 81.1 81.3 81.3 92.8 90.7 91.3 92.0 97.6 96.1 96 7 95-7 99.0 96.9 97-3 96.8 IOO.O IOO.O loo.o 96.7 97-0 98.7 98.0 100.0 V 2 8 32 128 512 1024 2048 4096 2 8 32 128 512 1024 2048 4096 The group consisting of strontium acetate and magnesium bromide, nitrate, formate and acetate will be considered next. There is nothing special to note in the case of strontium acetate. It is readily hydrolyzed, and any irregularities might easily be attributed to this fact. Attention might be called, however, to the increase in percentage dissociation with rise in temperature. It is interesting in considering the data of the four mag- nesium compounds to discover, if possible, the effect of the different anions. Of course, the water of crystallization would also be a factor. This is the same, however, in the case of the bromide and nitrate, and any difference in the conductivity of these two compounds may correctly be attri- buted to the different anions. On examining the data for these substances, it is readily seen that the conductivity of magnesium bromide is decidedly greater than that of magnesium nitrate. Its temperature coefficient of conductivity is also larger. This would point 21 to some difference in the anions either as to velocity or com- plexity. Apart from their remarkable similarity, magnesium acetate and formate present nothing of special interest. Strontium Acetate The strontium was precipitated and weighed as the car- bonate. Table XXV Conductivity V 12. 5 25 35 2 34-94 49.26 66.52 81.11 8 56.51 80.19 106 . 96 129.99 32 70.69 100.20 135-25 164.88 128 81.89 II7.I9 I57-69 193-44 512 88.50 128.09 170. 16 209.22 1024 91.18 131.09 177-44 218.24 2048 97-30 139.01 180.07 219.77 4096 97.89 139.60 184.44 224.75 Table XXVI Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 2 I-I5 3-29 1-38 2.80 I .46 2. 2O 8 1.89 3-35 2.1 4 2.67 2.30 2-15 32 2.36 3-34 2.80 2.79 2.96 2. 19 128 2.82 3-44 3-24 2.77 3-58 2.27 512 3-17 3-58 3-37 2.63 3-91 2.30 1024 3-19 3-50 3-70 2.82 4.08 2.30 2048 3.34 3.43 3.28 2.36 3.97 2.21 4096 3-34 3-4i 3-59 2.57 4.03 2.19 Table XXVII Percentage Dissociation 12. 5 25 35' 2 35-7 35-3 36.1 36.1 8 57-7 57-4 58-0 57-8 32 72.2 71.8 73-4 73-4 128 83-6 83-9 85-5 86.1 512 90.4 91.7 92.3 93-1 1024 93-i 93-9 96.4 97.1 2048 99 3 99.6 97-7 97-8 4096 100.0 100.0 ioo. o ioo. o 22 Magnesium Bromide The magnesium was prcipitated as ammonium magnesium phosphate, and weighed as the pyrophosphate. Table XXV 1 1 IConductivity V 12. 5 25 35 2 76.34 104.05 132.92 162.25 8 93-73 130.12 170.64 206.18 32 104.56 147-24 194-42 235.51 128 113.52 159-94 211.91 257.31 512 118.93 167.72 223.06 270.40 1024 122.80 173-39 230.94 279.38 2048 127.28 179.74 238.70 289.52 4096 130.91 185.06 244.94 305-94 Table XXIX Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 2 2.22 2.91 2.31 2.22 2.93 2 . 2O 8 2.91 3.11 3.24 2.49 3.55 2.08 32 3.41 3.26 3.77 2.56 4-II 2. II 128 3.71 3.27 4.16 2.60 4.54 2.14 512 3.90 3.28 4.43 2.64 4.73 2.12 1024 4.05 3.30 4.60 2.65 4.84 2.10 2048 4.20 3.30 4.72 2.63 5.08 2.13 4096 4-33 3-31 4-79 2.59 6.10 2.49 Table XXX Percentage Dissociation V 12. 5 25 C 35 2 58.3 56.2 54.3 53.0 8 71.6 70.3 69.7 67.4 32 79.9 79.5 79.4 76.9 128 86.8 86.4 86.5 84.1 512 90.9 90.6 91.1 88.3 1024 93.9 93.7 94.3 91.3 2048 97.3 97.1 97.5 94.6 4096 100.0 100.0 100.0 loo.o Magnesium Nitrate > The magnesium was weighed as the pyrophosphate. Table XXXII Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per units cent. units cent. units cent. 2.76 3.10 2.99 2.42 3.10 i-93 3-23 3-18 3-61 2-54 3-61 i-93 3-58 3-23 3-54 2.28 4.29 2. 10 3-74 3-14 4.41 2.66 4-44 2.OI 3-97 3-28 4-34 2-55 4.78 2.12 3-99 3-23 4-52 2.61 5-04 2. II 4.06 3-30 4-47 2.57 4.80 2.09 23 Table XXXI Conductivity V 12. 5 25 35 8 88.91 123.42 160.86 191.88 32 101.55 14* -97 187.10 223.24 128 110.78 155-50 204.72 247.66 512 119.01 165.77 220.89 265.33 1024 120.68 170.27 224.49 272.30 2048 123.34 173-18 229.70 280.09 4096 122.89 I73-70 229.58 277.54 8 32 128 512 1024 2048 4096 Table XXXIII Percentage Dissociation V 12. 5 25 35 8 72.1 71.1 70.0 68.5 32 82.4 81.7 81.5 79.7 128 89.9 89.5 89.1 88.4 512 96.5 95.4 96.2 94.7 1024 97.9 98.0 99.7 97.2 2048 100.0 99.7 100.0 loo. o 4096 99.7 ioo. o 99 96 99.1 Magnesium Formate The magnesium was weighed as the pyrophosphate. Table XXXIV Conductivity V 12. 5 25 35 2 37-33 52.53 69.24 83.25 8 58.15 83.44 109.29 132-14 32 74.68 106.05 141-71 172.3! 128 85.99 122.17 164.06 200.30 512 88.58 123.84 167.86 205.44 1024 94.03 133-87 176.23 209.90 2048 97.22 138.60 184.73 226.37 4096 97.18 138.74 182.91 223.19 24 Table XXXV Temperature Coefficients 0-12.5 12. 5-25 25-35 ( Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 2 1.22 3.27 1.33 2.53 1.40 2.02 8 2.02 3.47 2.07 2.48 2.29 2.10 32 2.51 3.36 2.85 2.69 3.06 2.16 128 2.89 3.36 3.35 2.74 3.62 2.21 512 2.82 3.18 3.52 2.84 3.76 2.24 1024 3.19 3.39 3.38 2.52 3.37 1.91 2048 3.31 3.40 3.69 2.66 4.16 2.25 4096 3.32 3.42 3.53 2.54 4.03 2.20 Table XXXVI Percentage Dissociation V 12. 5 25 35 2 38-4 37-9 37-5 36.8 8 59.8 60. i 59.2 58.4 32 76.8 76.4 76.7 76.1 128 88.4 88.1 88.8 88.5 512 91.1 89.3 90.9 90.7 1024 96.7 96.5 95.4 92.7 2048 99.9 99-9 100.0 100.0 4096 100.0 loo.o 99.05 98.6 Magnesium Acetate The magnesium was determined as in the preceding salt. Table XXXVII Conductivity V 12. 5 25 35 4 37-56 54-50 72.50 88.92 8 46.35 66.76 89.79 109.86 32 60.99 87.97 119.31 146.20 128 71.13 103.35 I39-5I 172.35 512 78.05 113-23 I53-4I 189-50 1024 80.38 116.73 158.95 201.71 2048 83.85 121.36 164.72 203.07 4096 84.99 121.76 165.38 203.70 Table XXXVIII Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 1.36 3.62 i-44 2.64 1.64 2.26 8 1.63 3.52 1.84 2.76 2.01 2.24 32 2.16 3.54 2.51 2.85 2.69 2.25 128 2.58 3.63 2.89 2.80 3.28 2.35 512 2. Si 3.60 3.21 2.83 3.61 2.35 1024 2.91 3.62 3.38 2.89 4.28 2.69 2048 3.00 3.58 3.47 2.86 3.84 2.33 4096 2.94 3.46 3.49 2.87 3.83 2.32 44-2 44.8 43-8 43-7 54-6 54-8 54-3 53-9 71.8 72.2 72.1 71.8 83.7 84.9 84-3 84.6 91.9 93-0 92.8 93-0 94.6 95-9 96. i 99.0 98.7 99-7 99.6 99-7 Table XXXIX Percentage Dissociation V 12. 5 25 35' 4 8 32 128 512 1024 2048 4096 100. o ioo. o ioo. o ioo. o The next group taken up for study consists of cadmium chloride, cadmium bromide, cadmium iodide and lead chlor- ide. Attention should be called to the fact that cadmium iodide, having no water of crystallization, has just about the same temperature coefficients of conductivity as cadmium bromide and cadmium chloride, both of which have water of crystallization. Apparent increase of percentage dissocia- tion with rise in temperature is unusual, and is quite notice- able in the case of cadmium iodide. Lead chloride has no water of crystallization but, like cadmium iodide, has high temperature coefficients of conduc- tivity. There must be some factor operative here affecting temperature coefficients just as hydration does, but which, from the nature of the case, cannot be due to hydrates. Cadmium Chloride Silver nitrate was used to precipitate the halogen in cad- mium chloride, bromide and iodide. Table XL Conductivity V 12. 5 25 35 4 33-65 46.21 60.15 71.92 8 45-32 60.85 79-30 94-59 32 65-63 90-33 II8-55 142.48 128 88.34 122.98 162.32 I95-7I 512 106. 14 148.36 197-57 236.99 1024 113.78 I59-65 212-53 258.73 2048 121 . 19 166.23 221.36 269.00 4096 121.03 172.78 232.06 282.43 26 Table XLI Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 I - 2.97 I . 12 2.42 1.18 1.96 8 1.24 2.74 1.47 2.42 1.53 1.93 32 1-97 3-oi 2.26 2.50 2.39 2.02 128,3 2.77 3-14 3-15 2-54 3-34 2.06 512 3.38 3.18 3-94 2.66 3.94 1.99 1024 3.67 3.23 4-23 2.65 4.62 2.17 2048 3 . 60 2.97 4.41 2 . 65 4 . 76 2.10 4096 4.14 3-42 4-74 2.62 5.04 2.12 Table XLII Percentage Dissociation v 12. 5 25 35 4 27.8 26.7 25.9 25.5 8 37-4 35-2 34-2 33-5 32 54-2 52.3 5i-i 50-5 128 72.9 71.2 69.9 69.3 512 87.6 85-9 85-1 83.9 1024 93 9 92.4 91.6 91.6 2048 100.0 96.2 95-4 95-3 4096 99 9 IOO.O IOO.O IOO.O Cadmium Bromide Table XLI 1 1 Conductivity V 12. 5 25 35 4 28.63 40-59 53-40 64.51 8 37-80 53-36 70.44 84.81 32 57.78 82.06 109.34 132.69 128 79-77 H3-57 I5I-23 184.16 512 101.37 I43-25 190.52 232.83 1024 110.69 156.85 208 . 48 252.81 2048 121.23 170.89 227.41 275.22 4096 123.76 I74-05 232.20 280.84 Table XLI V Temperature Coefficients 0-12.5 12. 5-25 25-35< Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 0.96 3-35 I .02 2.51 I . II 2.07 8 1.24 3-28 i-37 2.56 i-44 2.03 32 1.94 3-35 2.18 2.66 2.34 2.14 128 2.70 3-38 3-01 2.65 3-29 2.18 512 3-55 3-30 3-78 2.64 4-23 2.22 1024 3-69 3-33 4-13 2.62 4-43 2. 12 2048 3-97 3.21 4-52 2.64 4.78 2. 10 4096 4.02 3-25 4-65 2.67 4.86 2.79 27 Table XLV Percentage Dissociation V 12. 5 25 35 4 23.1 23-3 23.0 23.0 8 30-5 30.6 30-3 30.2 32 46.7 47.1 47.1 47-3 128 64.4 6 5 .2 6 5 .I 65-6 512 81.9 82.3 82.1 82.9 1024 89.4 9O. I 89.8 90.0 2048 97 9 9 8.2 97-9 98.0 4096 100.0 ioo. o ioo. o ioo. o Cadmium Iodide Table XLV I Conductivity V 4 20.45 12. 5 29.76 25 39-84 35 48.41 8 24-31 35-85 48.44 59-43 32 39-45 59-23 81-53 101 .22 128 62.73 93-36 127.36 157-35 512 87.06 127.74 172.93 2 1 1 . 90 1024 96.31 140.03 188.66 231.10 2048 109.01 157.20 209.73 256.42 4096 118.78 I7O.69 224.93 271.27 Table XLV 1 1 Temperature Coefficients 0-12.5 12. 5-25 25-35 ( Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 0-75 3-67 0.8l 2.72 0.86 2.16 8 0.92 3.78 I .01 2.82 I.IO 2.27 32 1.58 4-01 I. 7 8 3-01 1.97 2.42 128 2-45 3-90 2.72 2.91 3.00 2.36 512 3-25 3-73 3-62 2.83 3-90 2.26 1024 3-57 3.7i 3-82 3-7i 4.24 2.25 2048 3-86 3-54 4-20 3-67 4.67 '2.2 3 4096 4.15 3.49 4.34 2.54 4.63 2.06 Table XLV HI Percentage Dissociation V 12. 5 25 35 4 17.2 17.4 17.7 17.8 8 20.5 21 .O 21-5 21.9 32 33-2 34-7 36.3 37-3 128 52.8 54-7 56.6 58.0 512 73-3 74-8 76.9 78.1 1024 81.0 82.6 83-9 85-2 2048 91.7 92.1 93-3 94.5 4096 100.0 100.0 100.0 IOO.O 28 Lead Chloride The lead was precipitated by means of sulphuric acid and weighed as lead sulphate. Table XLIX Conductivity V 12. 5 25 35 64 104.41 144.76 188.71 224.76 128 116.27 161.56 211.43 252.17 512 133-10 186.16 246.31 293-05 1024 136.89 191.98 253-96 306.43 2048 138.88 195.16 258.49 312.13 4096 144.70 204 . 36 270.26 327.80 Table L Temperature Coefficients 0-12.5 12. 5-25 25-35< Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 64 3-23 3-09 3-52 2-43 3-61 I.9I 128 3-63 3.12 3-99 2.47 4.07 i-93 512 4-25 3-19 4.81 2.58 4.67 1.90 1024 4.41 3-22 4.96 2.58 5-25 2.07 2048 4-50 3-24 5-07 2.60 5-36 2.07 4096 4-77 3-30 5-27 2.58 5-75 2.13 Table LI Percentage Dissociation V 12. 5 25 35 64 72.2 '70.8 69.8 68.6 128 80.4 79.0 78.2 76.9 512 92 .o 91 . i 91 . i 89.4 1024 94.6 93.9 94.0 93.5 2048 96.0 95.5 95.6 95.2 4096 100.0 100.0 100.0 100.0 The aluminium and chromium compounds will be taken up next for discussion. In these compounds we should expect to find strong resemblances. These are very apparent. Chromium and aluminium compounds, with respect to their conductivities, are in a class by themselves. Their very large conductivities and their exceedingly large temperature coefficients must attract attention. Their very large conduc- tivities are due mainly to the great number of ions into which they are capable of ionizing and to hydrolysis. Judging from 29 their water of crystallization and from freezing point lowerings, 1 they must be hydra ted to an enormous extent. Their large tem- perature coefficients of conductivity would also indicate this to be the fact. The change in conductivity, both with rise in tempera- ture and with dilution, is much more gradual in the case of the aluminium salts than with those of chromium. The ex- tremely small percentage dissociation in concentrated solu- tions, in the case of chromium sulphate and aluminium sul- phate, is worthy of notice. This is probably connected with the fact that sulphates, especially in concentrated solution, undergo marked polymerization. Aluminium Chloride The aluminium was determined by precipitating the hy- droxide and weighing as the oxide A1 2 O 3 . This was done also in the case of aluminium nitrate and aluminium sulphate. Table LI I Conductivity o 12. s 25 35 ( 4 105.90 147.40 I93-5I 232.54 8 120.22 168.23 220.86 266.58 32 142.21 20O . 06 265.12 322.18 128 162.66 231.08 308 . 80 377.28 512 176.77 252.75 341-24 421 .06 1024 184.58 266.73 360.56 446.95 2048 193-37 279.49 381.44 472.46 4096 199.03 290.06 398.79 499.92 Table LIII Temperature Coefficients 0-12.5 12. 5-25 25-35< 4 8 32 128 512 1024 2048 4096 Cond. Per units cent. 3-32 3-H 3.84 3-19 4.63 3-26 5-47 3-36 6.08 3-07 6-57 3-55 6.89 3-56 7.28 3-66 Cond. units 4.21 5-2i 6.22 7.08 7-51 8.16 8.70 Per cent. 2.50 2.50 2 .60 2.69 2.80 2.82 2 .92 3.00 Cond. Per units cent. 3-90 2.02 4-57 2.07 5-7i 2.15 6.85 2.22 7-98 2-34 8.64 2.40 9. 10 2-39 IO. II 2-54 i Jones and Getman: Am. Chem. J., 31, 303 (1904). Publication No. 60, Car- negie Institution of Washington. 30 Table LIV Percentage Dissociation V 12. 5 25 35 4 53.2 50.8 48.5 46.5 8 32 128 512 1024 2048 4096 loo.o 100.0 100.0 loo.o Aluminium Nitrate Table LV Conductivity 60.4 58.0 55-4 53-3 71 .5 69.0 66.5 64-4 81.7 79-7 77-4 75-5 88.8 87.1 85-5 84.2 92.8 91.9 90.4 89.4 97-2 96.3 95-6 94-5 V 12. 5 25 35 4 102.82 139.22 180.52 216.54 8 115.67 158.84 206 . 89 248 . 82 32 136.32 188.54 247 - 70 299.96 128 156.18 217.14 287.05 349-49 512 166.97 234-8I 3I3-05 384-43 1024 173-45 247.08 332.20 410.18 2048 179.32 255-68 345-82 428.32 4096 187.89 272.12 372.07 462.84 Table LVI Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 2.91 2.8 3 3-30 2-37 3.60 1.99 8 3-45 2.98 3-84 2.42 4.19 2.03 32 4.18 3-07 4-75 2-51 5-23 2. II 128 4.88 3.12 5.60 2.58 6.2 5 2.18 512 5-45 3-25 6.28 2.67 7.17 2.28 1024 5-93 3-40 6.86 2.77 7.86 2.36 2048 6. 19 3-44 7-31 2.8 3 8-37 2-39 4096 6.90 4-53 8.19 2-95 9-32 2-45 Table LVI I Percentage Dissociation 12. 5 ' 25 35' 4 54-7 51-2 48.5 46.8 8 61.6 58.4 55-6 53-8 32 72.5 69-3 66.6 64.9 128 83-1 79-8 77-i 75-6 512 88.9 86.3 84.1 83-1 1024 92-3 90.8 89-3 88.7 2048 95-4 94-0 92.9 92.6 4096 loo.o ioo. o 100.0 100.0 Aluminium Sulphate Table LV II I Conductivity V 12. 5 25 35 4 51.90 71-81 92.40 107.72 8 65.21 89.81 114-44 i3 2 -4 6 32 89.50 123.63 158.01 183.51 128 121.87 169.38 219.04 266.22 512 164.08 230.86 301.01 358.79 1024 191-95 271.31 359-i6 433-51 2048 222.31 317-20 425-03 518.19 4096 262.35 378.23 514-06 634.78 Table LIX Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 1-59 3-06 1.65 2.30 1.53 1.66 8 1-97 3-02 i 97 2.19 i. 80 1.57 32 2 . 73 3-05 2-75 2.23 2.55 1.61 128 3.80 3.12 3-97 2.34 4.72 2.16 512 5-34 3.25 5-6i 2-43 5.78 1-79 1024 6 . 34 3-30 7-03 2.59 7.44 2.07 2048 7 - 59 3-41 8.63 2.72 9.32 2.19 4096 9.27 3-53 10.87 2.87 12.07 2.35 Table LX Percentage Dissociation V 12. 5 25 35 4 19.8 19.0 18.0 17.0 8 24-9 23-7 22.3 20.9 32 34-i 32.7 30.7 28.9 128 46-5 44-8 42.6 41.9 512 62.5 61.0 58.5 56.5 1024 73-2 71.7 69.9 68.3 2048 84-7 83-9 82.7 81.6 4096 IOO.O IOO.O IOO.O IOO.O Chromium Chloride The chromium was weighed as the oxide Cr 2 O 3 in the case of both chromium chloride and chromium sulphate. 32 Table LXI Conductivity V 12. 5 25 35 . 4 86.30 116.97 I53-32 199. 10 8 104.53 138.83 184.18 243-55 32 130.03 182.75 245-00 319.15 128 162.34 231.28 3I3-45 393.62 512 188.46 272.50 372.34 465 . 10 1024 200 . 2 I 294-55 403-58 504.31 2048 214.48 3I6.6O 434-36 543-02 4096 229.73 34I-I4 467.61 580.16 Table LXII Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units. cent. 4 2-45 2.84 2.91 2.49 4.58 2.99 8 2.74 2.62 3-63 2.62 5-94 3-23 32 4.22 3-25 4.98 2-73 7-42 3-03 128 5-52 3-40 6-57 2.84 8.02 2-55 512 6.72 3-57 7-99 2.93 9.28 3-95 1024 7-54 3-77 8.72 2. 9 6 10.07 2.50 2048 8.18 3-82 9.42 2.98 10.87 2.50 4096 8.91 3-88 10. 12 2.97 11.26 2.41 Table LXIII Percentage Dissociation V 12. 5 25 35 4 37-6 34-3 32-8 34-3 8 45-5 40.7 39-4 42.0 32 56.6 53-6 52-4 55-0 128 70.7 67.8 67.0 67.9 512 82.1 79-9 79-6 80.2 IO24 8 7 -2 86.4 86.3 86.9 2048 93-3 92.9 92.9 93-6 4096 IOO.O IOO.O IOO.O IOO.O Chromium Sulphate Table LX IV Conductivity V 12. 5 25 35 4 58.14 78.48 99.64 II6.4I 8 77-85 103.64 I30.I8 I5LI7 32 120.59 158.67 197.34 230.37 128 169.08 225.60 283.56 338.67 512 215-36 292.66 376.23 472.16 1024 240 . 48 329-96 459.83 561.76 2048 293-38 405.65 534-55 708.14 4096 3I3-39 445 16 598.46 808.29 33 Table LXV Temperature Coefficients 0-12 .5 12 ,5-25 25 -35 Cond. Per Cond. Per Cond. Per units cent. units cent. units cent. 1.6 3 2.80 I .69 2.15 1.68 1.69 2.06 2.6 5 2.12 2.05 2. 10 1.61 3-05 2-54 2.46 3-30 1.67 4-52 2.6 7 4.64 2.06 5-51 1.94 6.18 2.87 4.69 I. 60 9-59 2.55 7.16 2.98 10.39 3-15 IO. IO 2.22 8.98 3.06 10.31 2-54 17.36 3-25 10.38 3-29 12.26 2-75 20.98 3-51 4 8 32 128 512 1024 2048 4096 Table LXVI Percentage Dissociation V 12. 5 25 35 4 18.4 17.6 16.6 14.4 8 24.7 23.3 21.7 18.7 32 38.2 35.6 33.0 28.5 128 53.6 50.7 47.4 41.9 512 68.3 65.7 62.8 58.5 1024 76.2 74.1 76.8 69.5 2048 93.0 91.1 89.3 87.7 4096 100.0 ioo. o loo. o loo. o In the next group will be considered manganous sulphate, silver nitrate, copper sulphate and cobalt bromide. Man- ganous sulphate calls for no comment. The data obtained for silver nitrate are remarkably similar to those obtained for ammonium nitrate. It apparently behaves as any other ordinary, unhydrated, binary compound. It differs from ammonium nitrate in that its percentage dissociation, appar- ently decreasing with rise in temperature from o to 25, in- creases somewhat at 35. The data for copper sulphate resemble strikingly those ob- tained for manganous sulphate, cadmium bromide and cad- mium iodide. At ordinary temperatures manganous sulphate and copper sulphate have the same amount of water of crys- tallization. That their temperature coefficients should be approximately the same is not surprising; but that the tem- perature coefficients of cadmium chloride and cadmium bro- mide, crystallizing with less water, and cadmium iodide, crystallizing with no water, should be the same is surprising. 34 The temperature coefficients of conductivity of cobalt bromide indicate much hydration, as would be expected from its water of crystallization. Manganous Sulphate The manganese was weighed as the pyrophosphate. Table LX VI I Conductivity V 12. 5 25 35 4 37-25 5i-8o 67.17 79.11 8 44.11 .61.37 79.77 94.06 32 59.65 83.47 109.27 129.72 128 79.46 IH-74 147.24 I76.IO 512 97-99 138.76 184.58 222.69 1024 107.12 152.31 202.94 245.72 2048 116.15 165.28 221.33 268.33 4096 124.47 177-56 238.20 289.39 Table LXVIII Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Pa- Cond. Per Cond. Per V units cent. units cent. units cent. 4 1.16 3-" 1.23 2.38 I.I9 1.77 8 1.38 3.13 i-47 2.40 1.43 1.79 32 1.91 3-20 2.06 2.47 2.05 1.88 128 2.58 3.25 2.84 2.54 2.89 1.96 512 3.26 3-33 3-67 2.64 3.81 2.06 1024 3 . 62 3-38 4-05 2.66 4.28 2. i i 2048 3-93 3.38 4.48 2.71 4.7O 2.12 4096 4.25 3.42 4-85 2.73 5.12 2.15 Table LXIX Percentage Dissociation V 0* 12. 5 25 35* 4 29.9 29.2 28.2 27.3 8 35-4 34.6 33.5 32.5 32 47-9 47.0 45.9 44.8 128 63-8 62.9 61.8 60.8 512 78.7 78.1 77-5 76.9 1024 86.1 85.8 85.2 84.9 2048 93-3 93-i 92 . 9 92 . 7 4096 100. o 100. O IOO.O IOO.O 35 Silver Nitrate The silver was weighed as the chloride. Table LXX Conductivity V 12. 5 25 35 4 51-43 70.55 91.63 109.95 8 56.01 76.68 99.80 120.37 32 61.80 85.30 III .20 I33.I4 128 65.79 91 .06 119.14 142.67 512 69.24 94-99 125.23 148.77 2048 69.83 96.67 I26.8I 151.24 4096 71.03 99-03 129.68 153.32 Table LXX I Temperature Coefficients 0-12.5 12. 5-25 25-35' Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 L53 2. 9 8 1.69 2.40 1.83 2.OO 8 1.6 5 2-95 1.6 5 2-15 2.O6 2.O6 32 1.88 2-94 2.07 2.43 2.19 1.97 128 2. 02 2-94 2.25 2.47 2-35 1.97 512 2.O6 2. 9 8 2.42 2-55 2-35 1.87 2048 2.15 3.01 2.41 2-49 2.44 I .92 4096 2.24 3-15 2-45 2.47 2.36 1.82 Table LXXII Percentage Dissociation V 12. 5 25 35 4 72.4 71-3 70.6 71.7 8 78.8 77.4 76.9 78.5 32 87.0 86.2 85.7 86.8 128 92.6 92.0 91.8 93.1 512 97.4 95.9 96.5 97.0 2048 98.3 97.6 97.7 98.7 4096 100. o ioo. o 100.0 100.0 Cobalt Bromide This salt was precipitated by means of silver nitrate, and the bromine determined from the weight of silver bromide obtained. Table LXXI 1 1 Conductivity V 12. 5 25 35 4 87.82 I2O.24 I55-60 196.30 8 95-04 131.29 171.30 204 . 48 32 105 56 147.10 193.09 233.04 128 115.88 162. 19 2I4.O2 259.9I 512 119.47 169.42 224.49 273-44 1024 120.80 173.38 23L56 28l.l6 2048 124.00 174.68 234.28 282.65 4096 125-45 177.93 236.78 289.34 Table LXXIV Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 2-59 2-95 2.83 2-35 4.07 2.62 8 2.90 3-05 3-20 2.44 3-32 1.94 32 3-32 3-15 3.68 2.50 4-00 2.07 128 3-71 3-20 4.15 2.56 4-59 2.15 512 4.0O 3-35 4.41 2.60 4.90 2.18 1024 4.21 3-49 4-65 2.68 4.96 2.14 2048 4-05 3-27 4-77 2.73 4.84 2.07 4096 4.20 3-35 4.71 2.65 5.26 2.22 Table LXXV Percentage Dissociation V 12. 5 25 35 4 70.0 67.6 65.7 67.8 8 75-7 73-8 72.3 70.7 32 84.1 82.7 81.5 80.5 128 92-3 92 .0 90.4 89.8 512 95-2 95-2 94-8 94-5 1024 96.3 97-5 97-8 97-2 2048 98.8 98.2 98.9 97-7 4096 100. 100. IOO.O IOO.O Copper Sulphate The sulphuric acid in this salt was precipitated and weighed as barium sulphate. 37 Table LX XV I Conductivity V 12. 5 25 35 2 3- 6 42.12 55- 1 * 6 5 - r 5 8 42.30 59.35 77.33 91.16 32 57-24 80.53 105.64 124.94 128 76.91 108.74 143.21 170.60 512 97.88 138.92 184.97 221.08 1024 105.85 150.86 202.57 245.05 2048 113.36 161.78 217.71 264.44 4096 119.18 171.07 231.27 281.42 Table LX XV 1 1 Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. units Per cent. Cond. units Per cent. Cond. units Per cent. 0.96 3 19 I .04 2.47 I .00 .82 1.36 3-22 1.44 2-43 1.38 79 1.86 3-25 2.01 2.50 i-93 83 2-54 3-30 2.76 2-54 2.74 .91 3-28 3-35 3-68 2.65 3.61 95 3.60 3-40 4.14 2-74 4-25 2. 10 3-87 3 -4 1 4-47 2.76 4.67 2.15 4-15 3-48 4.82 2.82 5.02 2.17 V 2 8 32 128 512 1024 2048 4096 Table LXXVIII Percentage Dissociation V 12. 5 25 35 2 25.2 24.6 23.8 23.2 8 35-5 34-7 33-4 32-4 32 48.0 47.1 45.7 44.4 128 64.5 63.6 61.9 60.6 512 82.1 81.2 80.0 78.6 1024 88.8 88.2 87.6 87.1 2048 95.1 94.6 94.1 94.0 4096 100. o 100. o 100. o loo.o The conductivity values obtained for uranyl sulphate and uranyl acetate do not agree satisfactorily with those ob- tained by West. 1 His solutions were evidently standardized on a different basis. It should be noticed that the tempera- ture coefficients, in conductivity units, of uranyl sulphate de- crease with rise in temperature through V = 512. After this dilution they increase, as in the case of the other uranyl salts. The percentage dissociation of uranyl acetate apparently 1 Am. Chem. J., 44, 537 (1910). 38 increases with rise in temperature through V = 128. The more dilute solutions show a decrease with rise in tempera- ture. This may be seen in the curve for uranyl acetate which follows. Uranyl Chloride The uranium in uranyl chloride, nitrate, sulphate and acetate was precipitated by means of ammonium hydroxide and weighed as the oxide U 3 O 8 . Table LX XIX Conductivity V 12. 5 25 35 4 101.45 139.09 180.45 214.70 8 110.48 157.64 206.01 246.51 32 I33-05 186.56 246 . I 2 297.84 128 148.39 209.75 279.00 339-40 512 I55'98 22O.7O 296.56 360.44 1024 161 .02 23I-37 311.92 383.88 2048 168.42 242.69 328.24 405 - 98 4096 174.98 254.22 348.16 433-68 Table LX XX Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V [units cent. units cent. units cent. 4 3.01 2-97 3-31 2.38 3-43 I .90 8 3-77 3-41 3-87 2.46 4-05 1.97 32 4.28 3-22 4.76 2-55 5-17 2. 10 128 4.91 3-31 5-54 2.64 6.04 2.17 512 5-i8 3-32 6.07 2-75 6-39 2.16 1024 5.63 3-50 6-44 2.78 7.20 2.31 2048 5-94 3-53 6.84 2.82 7-77 2-37 4096 6-34 3-62 7-52 2.96 8-55 2.46 Table LXXXI Percentage Dissociation 12. 5 25 35' 32 128 512 1024 2048 4096 58.0 54-7 51-8 49-5 63.1 62.0 59-2 56.8 76.0 73-4 70-7 68.7 84.8 82.5 80.2 78.2 89.1 86.8 85-2 83.1 92.0 91 .0 89.6 88.5 96.3 95-5 94-3 93-6 100. 100. IOO.O IOO.O 39 Uranyl Nitrate Table LX XXI I Conductivity V 12. 5 25 35 4 74-91 102.01 132.91 158.84 8 83.44 II4-7I I50-57 181.20 32 97.22 i3 6 -35 180.64 219.38 128 110.14 153-84 207.89 254.21 512 116.33 166.65 224.95 277.35 1024 123.14 I77-76 241.47 298.63 2048 128.92 187.20 255.38 317-44 4096 136.77 200.10 274.50 343-09 Table LXXXIII Temperature Coefficients 0-12.5 12. 5-25 25-35 2.90 2-47 2.42 2-59 i-95 3-oo 3-07 2.68 3-o6 2.03 3-22 3-54 2.60 3-87 2.14 3-32 4.16 2.67 4-63 2.23 3-47 4.66 2.80 5-24 2.33 3-55 5-io 2.87 5-72 2-37 3-62 5-46 2.92 6.21 2-43 3-7i 5-95 2-97 6.86 2.50 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 4 2.17 8 2.50 32 3-13 128 3.66 512 4.03 1024 4.37 2048 4 . 66 4096 5-07 Table LXXXIV Percentage Dissociation V 12. 5 25 35 4 54.8 51.0 48.4 46.3 8 61.0 57.3 54.9 52.8 32 71.1 68.1 65.8 63.9 128 80.5 77.9 75.8 74.1 512 85.0 83.3 82.0 80.8 1024 90.0 88.8 88.0 87.1 2048 94.2 93.6 93.1 92.5 4096 100. o ioo. o ioo. o ioo. o Uranyl Sulphate Table LXXXV Conductivity V 12. 5 25 35 8 78.13 99-77 120.82 136-43 32 100.65 129.52 156.80 176-52 128 128.62 166.72 203.02 229.42 512 157-54 207.90 257.69 295.20 1024 175-68 235.28 296.95 343-01 2048 191.68 260.77 332.57 391-00 4096 203.33 285.05 373-65 446.33 40 Table LXXXVI Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. - N Per V units cent. units cent. units cent. 8 i-73 2.22 1.68 1.68 1.56 .29 32 2.31 2.30 2.18 1.68 1.97 .26 128 3-05 2-37 2.90 i-74 2.64 30 512 4-03 2.56 3.98 1.91 3-75 .46 1024 4-77 2.72 4-93 2. 10 4.61 55 2048 5-53 2.89 5-74 2. 2O 5-84 .76 4096 6-54 3.22 7.09 2-49 7.27 95 Table LXXXVI I Percentage Dissociation V 12. 5 25 35" 8 32 128 512 1024 2048 4096 loo.o ioo. o loo.o ioo. o Uranyl Acetate Table LX XXV 1 1 1 Conductivity V 12. 5 25 35 38.4 35-0 32.3 30.6 49-5 45-4 42.0 39 -6 63-2 58.5 54-3 51-4 77-5 72.9 69.0 66.2 86.4 82.5 79-5 76.9 94.2 9i-5 89.0 87.6 8 30-59 42.75 56.53 68.12 32 39-65 55-08 72.25 86.67 128 51-48 70.66 91-34 108.52 512 63-57 86.06 110.47 129.06 1024 70.13 94-74 120.37 141 . 12 2048 76.81 103.65 131.78 154.46 4096 83-75 113.81 145.10 170.54 Table LXXXIX Temperature Coefficients 0-12.5 12. 5-25 25-35 Cond. Per Cond. Per Cond. Per V units cent. units cent. units cent. 8 0.97 3.12 I . 10 2-57 1.16 2-05 32 1.23 3.10 1-37 2-49 1.44 1.99 128 i-53 2.97 1-65 2-34 1.72 1.88 512 i. 80 2.8 3 i-95 2.26 1.86 1.68 1024 1.97 2.8l 2.05 2.16 2.08 i-73 2048 2-15 2.80 2.25 2.17 2.27 1.72 4096 2.41 2:88 2.50 2.20 2-54 1-75 36.5 37-6 39-0 40.0 47-3 48.4 48.8 50.8 61.5 62.1 63.0 63-7 75-9 75-6 76.1 75-7 83-7 83-3 83-0 82.8 91.7 91.1 90.8 90.6 Table XC Percentage Dissociation V 12. 5 25 35* 8 32 128 512 1024 2048 4096 ioo. o loo. o loo. o TOO. o FIGURES So far little or nothing has been said in regard to the per- centage dissociation of the salts studied. Attention will be called to these by means of curves. The curves of ten of the thirty salts showed the percentage dissociation to be almost a linear function of rise in temperature. Plotting percentage dissociation as ordinates against rise in temperature as ab- scissae, for each dilution, in ten cases out of the thirty, curves were obtained resembling the one for aluminium sulphate, Fig. I. The other 20 salts all showed variations in the maxima or minima. Some of these are very slight. Diagrams of the most striking variations follow. The salts giving curves showing the percentage dissociation to be a linear function of rise in temperature were acid ammonium sulphate, alu- minium nitrate, aluminium chloride, aluminium sulphate, uranyl chloride, uranyl sulphate, uranyl nitrate, chromium sulphate, cadmium chloride and manganous sulphate. The others showed more or less variations, the most striking being here represented. Fig. II is very interesting, showing in the case of cadmium iodide the increase in percentage dissociation with rise of temperature from V = 8 to V 2048. From the curve, Fig. Ill, it is easily seen that the percentage dissociation of chromium chloride increases decidedly with rise in temperature between 25 and 35. The increase becomes less and less as the dilution increases. Uranyl acetate shows an increase in percentage dissociation in the more concentrated solutions, but at greater dilutions gives a falling curve (Fig. IV) . 8o 60 40 30 2048 1024 512 128 20 I- 10 12.5 as Temperature Fig. I Aluminium Sulphate 35 43 2048 1024 512 128 12.5 25 Temperature Fig. II Cadmium Iodide - 8 35 44 2048 1024 512 128 12.5 25 Temperature Fig. Ill Chromium Chloride 35 45 2048 * 1024 512 JO * 12.5 25 Temperature Fig. IV Uranyl Acetate 35 700 - 12.5 25 Temperature Fig. V Silver Nitrate ZOO' 3 80 70 12.5 25 Temperature Fi. VI Magnesium Nitrate 47 Silver nitrate shows a decided increase in percentage disso- ciation with rise in temperature from V 4 to V = 2048. See Fig. V. The curves representing magnesium nitrate and magnesium bromide (Figs. VI and VII) show a remarkable resemblance. The maxima at higher dilutions are pronounced. 80 128 12.5 25 3 Temperature Fig. VII Magnesium Bromide An examination of the curves raised the question, what pro- duces this variation? The apparent increase in percentage dissociation with rise in temperature would, naturally, be thought to be due to hydration. When there is little or no hydration the question becomes more difficult to answer. If, however, the ions are assumed to be complex, rise in tem- perature would bring about greater dissociation, and the effect 4 8 would be just the same as if hydrates had been present. It is difficult to differentiate the two factors. That hydrates exist is not doubted. The complexity of the ions is not so well estab- lished, so that we shall present arguments only for the latter. If the change were a gradual increase, it might be attributed easily to hydration, but a change from an increase to a de- crease in dissociation could not be accounted for in this way; whereas complex ions once dissociated might reach a state where recombination would take place. Moreover, the amount of hydration has been found to depend on the amount of water of crystallization. In several of the preceding salts, notably in the case of cadmium compounds, cadmium iodide, which has no water of crystallization, is found to have temperature coefficients of conductivity equal in magnitude to those of cadmium chloride, cadmium bromide and copper sulphate, all of which have water of crystallization. Lead chloride, also, which has no water of crystallization, has temperature coefficients which compare well with those of substances that are much hydrated, i. e., copper sulphate and cobalt bromide. This would indicate that there must be some other factor present producing the same effect as hydration. SUMMARY 1. In the main the results obtained in the case of the thirty salts studied tend to confirm the earlier results. 2. Without exception conductivity increases with rise in temperature and with dilution. 3. The temperature coefficients of conductivity expressed in conductivity units, with two exceptions, increase with rise in temperature, while the temperature coefficients expressed in percentage decrease. 4. Salts greatly hydrated have large temperature coeffi- cients. The amount of hydration, judged by the tempera- ture coefficients, seems closely related to the water of crys- tallization. 5. The apparent exceptions to the results earlier obtained, viz., an increase in percentage dissociation with rise in tem- perature and a large temperature coefficient when there is no 49 reason to expect large hydration, point, in the opinion of the author, strongly to the view advanced above, that inductive action takes place through the solvent between charged ions and neutral molecules, and that this gives rise to complex molecules and ions in solution. After sufficient work has been done in this field, it is hoped to bring together all of the conductivity and dissociation data obtained in this laboratory and to publish them as a mono- graph. However, before this is done it is intended to repeat the work with every substance, where the repetition is not already completed starting with new material, repurifying, restandardizing and remeasuring the conductivity. Work will be continued in this laboratory along the lines indicated above, probably for at least the next ten years, and there will be six investigators working here in this field during the next academic year. BIOGRAPHY Lula Gaines Winston, the author of this dissertation, is a daughter of Professor Charles H. Winston, LL.D., of Rich- mond College, Virginia. Having graduated at the Richmond High School, she entered Richmond College and received the degree of B.S. in 1899. Since that time she has attended the Harvard Summer School for three years, taking courses in Chemistry and Physics. During the session 1901-1902, she was teacher of Science in the Richmond Female Seminary. In 1902 she was elected teacher of Chemistry and Physics in the State Female Normal School, Farmville, Virginia, which position she still holds, hav- ing been given leave of absence for the past two years to pursue her studies at Johns Hopkins University. GENERAL LIBRARY UNIVERSITY OF CALIFORNIA BERKELEY RETURN TO DESK FROM WHICH BORROWED This book is due on the last date stamped below, or on the date to which renewed, pks are subject to immediate recall. MAY 2 2 19& 1960 21-100m-l,'54(1887sl6)476 GAYLG3Q BROS. MAKERS SYRACUSE,- N.Y. P *T JAN. 21,1008