114 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



the degree of ionization. It has been proposed to take account of the 

 change of conductance due to the viscosity effect in direct proportion to 

 the fluidity change of the solution. 8 In that case the degree of ionization 

 of the electrolyte is given by the expression: 



/Af\\ & FO 



(40) Y = 2C7' 



where F a is the fluidity of the pure solvent and F that of the solution. 

 Other writers * have proposed an equation of the form: 



(41) Y = ^ 



where p is a constant, and A and A are ionic conductances. If p were 

 equal to unity, the conductance of the solution would be corrected in 

 direct proportion to the fluidity change. Difficulty arises in determining 

 the value of p. It has been suggested that the value of this constant 

 may be derived from the manner in which the speed of an ion in dilute 

 solution changes as a function of the temperature. As we shall see 

 presently, the change in the A values of the ions is not in general 

 directly proportional to the fluidity change of the solvent, but is in most 

 cases smaller. It has been shown that a relation of the type 



(42) A = KFP 



holds very nearly. 10 The values of the constant p for different salts are 

 given in Table XLII. 



TABLE XLII. 



VALUE OF THE VISCOSITY-TEMPERATURE EXPONENT p FOR 

 DIFFERENT IONS. 



Univalent Ions. 



Ion Cl- K + NH 4 + N0 3 - Ag + Na + CH 3 COO 



p 88 .887 .891 .807 .949 .97 1.008 



A 65.4 64.7 64.4 61.8 54. 43.5 34.6 



Divalent Ions. 



Ion 1/2S0 4 ~ 1/2 C A" 1/2 Ba" 1/2 Ca" 



p 0.944 .931 .986 1.008 



A 68.7 63.8 55.9 52.1 



)usfleld and Lowry, Phil. Trans. [A] 20k, 289 (1903) ; Noyes and Falk, J. Am. 



Washburn, J. Am. Chem. 8oc. S3, 1463 (1911). 

 "Johnston, J. Am. Chem. Soc. SI. 1010 (1909). 



