ELECTROLYTES IN MIXED SOLVENTS 187 



anhydrous solvents, there is all the more reason for believing that these 

 complexes exist when the salts are dissolved in pure water. 



4. Conductance in Mixed Solvents over Large Concentration Ranges. 

 A considerable number of systems have been studied in which salts 

 have been dissolved in mixtures of two solvents miscible in all propor- 

 tions. In these solutions the conductance has not been studied for small 

 additions of either component. As a rule, the concentration was varied 

 by intervals of 25 per cent. In such cases, the change in the viscosity of 

 the medium, as well as that in the ionization of the electrolyte, makes 

 itself felt. 



When the two solvents have approximately the same dielectric con- 

 stant and the dissolved salts are ionized to practically the same extent 

 in the two solvents, then the conductance of solutions in mixtures of these 

 solvents is determined primarily by the viscosity of the mixtures. In 

 other cases, where the viscosity change is small and the ionization of the 

 salt in the two solvents differs greatly, the form of the curve is largely 

 dependent upon the ionization change brought about by the change in 

 the composition of the mixture. 



In Figure 42 are shown values of the fluidity of mixtures of acetone 

 with water, methyl and ethyl alcohol at 0. 1S In Figure 43 are shown 

 fluidity curves for mixtures of methyl alcohol with water and ethyl 

 alcohol/ 4 and nitrobenzol with methyl and ethyl alcohols, 15 at 25. The 

 values are given in Table LXXV. In the case of these curves the precise 



TABLE LXXV. 



THE FLUIDITY OF MIXTURES AS A FUNCTION OF THEIR COMPOSITION. 

 Solvent Per Cent B 



= 



values are represented only for the pure solvents and the mixtures hav- 

 ing compositions of 25, 50 and 75 per cent, smooth curves having been 



"Jones, Bingham and McMaster, ZtscJir. f. phys. CJiem. 57, 193 (1906). 

 "Jones and Veazey, Conductivity and Viscosity in Mixed Solvents, Carnegie Reports, 

 p. 190 (1907). 



"Jones and Veazey, Ztsctir. f. phys. Chem. 62, 49 (1908). 



