120 Conductivities and Viscosities in Pure and in Mixed Solvents. 



lation to the simplest possible terms. 1 He also showed how the law of 

 independent migration velocities of ions could be used to calculate the 

 H ,, values of organic acids from those of their sodium salts. 2 In addition , 

 just after Arrhenius on the basis of his dissociation theory, had pointed 

 out 3 the necessity of the parallelism between the strengths of acids and 

 their conductivities, it was Ostwald who, led to similar ideas by other 

 considerations, succeeded in demonstrating 4 the existence of such a 

 relation and thereby made the first contribution to the application and 

 significance of conductivity in questions of chemical affinity. Further, 

 from thermodynamical considerations, Ostwald derived his " dilution 

 law," 5 which permits the calculation (from the molecular conductivities 

 of any weakly dissociated substance at different dilutions) of its affinity 

 constant, which is independent of the degree of dilution and is condi- 

 tioned only by the nature of the dissolved substance. During his 

 classical investigations in this field 6 Ostwald determined the affinity 

 constants of over 240 organic acids, and on the basis of these values 

 drew many conclusions as to the composition and constitution of acids, 

 thereby furnishing organic chemistry with a new and useful means of 

 investigating questions of constitution. 7 



In a word, whereas Kohlrausch made the determination of conduc- 

 tivity possible, by developing a convenient and accurate method of 

 measuring it, Ostwald pointed out the practical importance of these 

 measurements by indicating their bearing upon the solution of other 

 chemical problems. 



The first serious attempt to study the conductivity of alcoholic 

 solutions of organic acids was made in 1888 by Hartwig. 7 This investi- 

 gator employed the Kohlrausch method of measuring conductivity, and 

 worked with solutions of formic, acetic, and butyric acids of varying 

 concentrations, at temperatures ranging from to 30. He found 

 that conductivity increased with rise in temperature, and calculated the 

 temperature coefficients of conductivity by means of the equation 



No other conclusions, however, can be drawn from Hartwig's work, 

 because he expressed his results in terms of grams of acid in 100 grams 

 of solution instead of in terms of molecular concentrations. 



In 1889 Kablukoff 8 determined the conductivity of hydrochloric-acid 

 gas in absolute alcohol and in alcohol- water mixtures at 25. He found 

 the molecular conductivity in pure alcohol to be about one-sixteenth of 

 that in pure water. In the mixed solvent the conductivity increases 



>Zeit. phys. Chem., 2, 561 (1888). 6 Zeit. phys. Chem., 2, 36, 270 (1888). 



*Ibid.,2, 270 (1888); 3, 170 (1889). Amer. *Ibid., 3, 170, 241, 369 (1889). 



Chem. Journ.,46,66 (1911). 7 Wied. Ann., 2, 33, 58 (1888). 



Bib. t. k. Ak., 1884. 8 Zeit. phys. Chem., 4, 429 (1889). 

 Mourn, prakt. Chem., 30, 93 (1884). 



