142 Conductivities and Viscosities in Pure and in Mixed Solvents. 



for the determination of percentage dissociation will be worked out 

 here in the near future. Goldschmidt 1 obtained values for the limiting 

 conductivities of several organic acids in alcohol from thence values of 

 their sodium salts. These varied from 83 to 93, depending on the 

 nature of the acid. It has not yet been found practicable to determine 

 the limiting conductivities of the organic acids studied in this investi- 

 gation, but as a result of Goldschmidt's work it is certain that they do 

 not differ greatly from 90. If this be the case, the dissociation of the 

 organic acids investigated by the authors, as determined by conductivity, 

 do not in any case exceed 2 per cent, even in N/512 solutions. 



RELATION BETWEEN COMPOSITION AND CONDUCTIVITY. 



In his classical study of the conductivity of aqueous solutions of 

 organic acids, to which reference has already been made, Ostwald 2 

 pointed out a number of relations between composition and molecular 

 conductivity. The validity of these relations has been confirmed by 

 the work which has been in progress in this laboratory for the past 

 fifteen years. In view of this, an examination of the results obtained 

 for alcoholic solutions, in the attempt to discover similar relations, 

 should prove to be interesting. 



Take the following compounds: 



Maleic acid. Fumaric acid. Mesaconic acid. Itaconic acid. 



H-C-COOH HOOC-C-H HOOC-C-CH 3 CH 2 



II 11 II II 



H-C-COOH H-C-COOH H-C-COOH C-COOH 



I 

 CH 2 -COOH 



The conductivity of maleic acid (table 75) is many times that of 

 fumaric. This fact is in keeping with the results obtained in aque- 

 ous solution, 3 and with the present conception of the configuration of 

 these acids. Mesaconic acid is a methyl substitution product of 

 fumaric acid, and its conductivity is of the same order of magnitude 

 as that of fumaric acid. Itaconic acid, which is isomeric with mesaconic 

 acid, but which has very different constitution, shows much higher con- 

 ductivity. 



Malonic acid, at a volume at 32 and at 25, has a molecular conduc- 

 tivity of 0.055. Under the same conditions, ethylmalonic acid has a 

 conductivity of 0.083; diethylmalonic 0.080; propylmalonic 0.105; 

 dipropylmalonic 0.090; butylmalonic 0.036; allylmalonic 0.039; and 

 benzylmalonic 0.062. 



The above results show that the introduction of an ethyl group 

 increases the conductivity, while the introduction of a second ethyl group 



x Zeit. Elektrochem., 15, 4 (1909); Zeit. phys. Chem., 30, 627 (1910); 81, 30 (1912). Zeit. 

 Elektrochem., 20, 473 (1914); Zeit. phys. Chem., 89, 129 (1914). 

 2 Zeit. phys. Chem., 3, 170, 241, 369 (1889). 

 3 Carnegie Inst. Wash. Pub. No. 170, 113 (1912). 



