14 



CONDUCTIVITY AND VISCOSITY IN MIXED SOLVENTS. 



TABLE 2. Potassium iodide. 



From an examination of the above results it is seen that the conductivities 

 in the mixtures of water and alcohol are the greater until a dilution of 512 

 liters is reached. At higher dilutions the conductivity in the pure alcohol 

 becomes greater than that of the alcohol containing 20 per cent of water. 

 In general, however, Cohen found that addition of water increased the con- 

 ductivity, as we should expect. 



Lenz l measured the conductivities of various salts (potassium iodide, 

 bromide, and chloride, sodium chloride, etc.) in mixtures of methyl and 

 ethyl alcohols and water. He found that in certain cases the relative re- 

 sistances can be obtained from the equation 



r = 100 



where 100 is taken as the resistance of an aqueous solution of the same per 

 cent, v is the volume per cent of alcohol, and b a constant. The formula 

 holds best for the mixtures of methyl alcohol and water. 



Stephan 2 studied the conductivities of dilute solutions of sodium, potas- 

 sium and lithium chlorides, and sodium and potassium iodides in mixtures 

 of ethyl alcohol and water. 



Kablukoff 3 determined the conductivity of hydrochloric acid in ethyl 

 alcohol containing varying amounts of water. 



Arrhenius 4 investigated the changes in the conductivity of aqueous solu- 

 tions, resulting from the addition to them of small quantities (less than 10 

 per cent by volume) of non-electrolytes, such as methyl or ethyl alcohol, 

 cane-sugar, acetone, etc. He found that the changes could be expressed by 

 the empirical formula 



where I is the conductivity in water, 1 that in the mixture, x the volume 

 per cent of added non-electrolyte, and a a constant peculiar to each non- 

 electrolyte. Where two non-electrolytes were added a similar empirical 

 formula was found to hold. The coefficient differs not only for different 



1 Mem. de 1'Acad. de St. P6tersbourg, 



7, 30 (1881). 



2 Wied. Ann., 17, 673 (1882). 



3 Ztschr. phys. Chem., 4, 432 (1889). 



4 Ibid., 9, 487 (1892). 



