62 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



TABLE XXIV. 



VALUES OF K AND OF A FOR ELECTROLYTES IN DIFFERENT SOLVENTS. 



Solvent Solute Temp. C. K X 10* A 



Benzonitrile Nal 25 55.0 49.0 



Epichlorhydrin (C 2 H 5 ) 4 NI 25 48.5 62.1 



Propylalcohol Nal 18 45.0 20.6 



Acetone Nal 18 30.0 167.0 



Acetophenone Nal 25 34.0 35.6 



Methylethylketone Nal 25 23.0 139.0 



Pyridine Nal 18 13.0 61.0 



Isobutylalcohol Nal 25 12.0 13.7 



Acetoaceticester NaSCN 18 9.5 32.1 



Isoamylalcohol Nal 25 3.9 9.2 



Ethylenechloride (C 3 H 7 ) 4 NI 25 1.45 66.7 



The mass-action constant varies with the nature of the solvent. The 

 greatest value is that for benzonitrile, which is 55 X 10~ 4 , and the smallest 

 that for ethylenechloride, which is 1.45 X 10' 4 . The change in the value 

 of the ionization constant among the alcohols is of particular interest in 

 view of their relation to water. The constant for solutions in propyl 

 alcohol is 45 X 10~ 4 , in isobutylalcohol 12 X 10~ 4 , and in isoamylalcohol 

 3.9 X 10~ 4 . It is evident that, as the substituting hydrocarbon group 

 becomes more complex, the ionization constant decreases. These results 

 also have a bearing on the probable behavior of aqueous solutions. The 

 properties of solutions in the lower alcohols differ only inconsiderably 

 from those of aqueous solutions. It seems probable, therefore, that in 

 going from water through the lower alcohols to the higher alcohols the 

 change in the phenomenon underlying the ionization process undergoes 

 an alteration in degree rather than in kind. It might be concluded, 

 therefore, that in aqueous solutions, also, the mass-action law is ap- 

 proached as a limiting form. This question, however, will be discussed 

 at somewhat greater length in a succeeding chapter. 



A considerable number of data are available on the conductance of 

 dilute solutions in acetone. In the following table are given values of 

 the mass-action constant and the limiting values of the equivalent con- 

 ductance for a series of electrolytes in this solvent. 



TABLE XXV. 



VALUES OF K AND OF A FOR DIFFERENT ELECTROLYTES IN ACETONE AT 18. 

 Solute 10 4 K A 



KI 51.0 156 



Nal 39.0 156 



Lil 31.0 154 



