CONDUCTION PROCESS IN ELECTROLYTES 35 



where A is the equivalent conductance of the solution at the concentra- 

 tion C, and A is the limiting value which the conductance approaches 

 as the concentration decreases without limit. According to this theory, 

 we may calculate the fraction of electrolyte in an ionized condition, if 

 we know the equivalent conductance and the limiting value which the 

 equivalent conductance approaches at zero concentration. In Table III 

 were given values of the equivalent conductance of a number of electro- 

 lytes at a series of concentrations. The approximate limiting values 

 A , which the equivalent conductance approaches at low concentrations, 

 appear in the second column of that table. From these values we may 

 calculate the degree of ionization of the electrolytes at any concentration 

 falling within the intervals given. In the case of potassium chloride, 

 for example, A = 130.0, approximately, and the equivalent conductance 

 at normal concentration is 98.22. Therefore, the ionization of potassium 

 chloride at this concentration is approximately 75% ; that is, of the total 

 potassium chloride present in solution at this concentration, 75% is con- 

 cerned in the actual process of conduction and 25% takes no part in this 

 process. 



The ionization values of various electrolytes in water at 18 are given 

 in Table IV. 23 It will be observed that the ionization of salts of the 



TABLE IV. 

 IONIZATION VALUES OF ELECTROLYTES IN WATER AT 18. 



Concentra- 

 tion, C. 10- 8 2 x 10- 3 5 x 10- 3 10- z 2 X 10- 2 5 X 10-* 10' 1 2 X 10- 1 5 X- 10- 1 1.0 



NaCl 977 .969 .953 .936 .916 .882 .852 .818 .773 .741 



KC1 979 .971 .956 .941 .922 .889 .860 .827 .779 .742 



Lid 975 .966 .949 .932 .911 .878 .846 .812 .766 .737 



RbCl 980 942 855 748 



CsCl 978 .969 .954 .937 847 



T1C1 976 .965 .942 .915 



KBr 978 .970 .955 .940 .921 .888 .859 .825 .766 .... 



KI 978 .970 .956 .941 .922 .890 .869 773 .727 



KSCN 978 .970 .955 .940 .920 .888 .860 



KF 978 .970 .954 .937 .915 .878 



NaF 974 .964 .945 .925 .899 .854 



T1F 961 .936 .908 .865 



NaK0 3 977 .968 .950 .932 .910 .871 .832 .788 .719 .660 



Noyes and Falk, J. Am. Chem. Soc. 34, 454 (1912). 



In calculating the ionization at the higher concentrations Noyes and Falk have cor- 

 rected for the viscosity change of the solution due to the added electrolyte. While there 

 is every reason for believing that the change in the viscosity of the solution entails a 

 change in the speed of the carriers, in general, the change in speed is probably not directly 

 proportional to the change in the fluidity of the medium. All ionization values at higher 

 concentrations, therefore, are more or less in doubt. As a rule the viscosity effects are 

 small at concentrations below 10' 2 N. In comparing the ionization of various electrolytes, 

 therefore, it is best to choose concentrations at which the viscosity effect may be neglected. 



