FORM OF THE CONDUCTANCE FUNCTION 87 



value of the constant m, a given deviation occurs at the lower concen- 

 tration, the greater the value of D/K. Thus, sodium iodide and silver 

 nitrate both have a value of the exponent m = 0.83, while the values of 

 D/K are 1.54 and 1.29 respectively. Correspondingly, the values of the 

 ion concentrations for a 5% increase of the function are 0.63 and 0.78 

 respectively. The value of D/K for typical electrolytes in ammonia lies 

 in the neighborhood of iOO. For weak electrolytes the value of D/K 

 appears to be larger, as for example for cyanacetamide and potassium 

 amide. In the case of silver iodide, however, which appears to be a very 

 exceptional electrolyte, the value of D/K is extremely small. As we shall 

 see below, the value of D for a given electrolyte is relatively independent 

 of the nature and condition of the solvent. At higher temperatures, the 

 dielectric constant of the solvent decreases and with it there is a large 

 decrease in the value of the constant K, while the constant D remains 

 practically fixed. At higher temperatures, therefore, the value of D/K 

 will increase. This tends to increase the deviations from the simple 

 mass-action relation. On the other hand, the value of m increases with 

 increasing temperature and decreasing dielectric constant, and this tends 

 to make the percentage deviations from the simple mass-action relation 

 smaller. The observed effect will be the resultant of these two. From 

 the known form of the conductance curve in solvents of very low dielec- 

 tric constant, it is evident that ultimately the effect due to the increase 

 in the value of D/K overbalances that due to the increase in the 

 value of m. 



Corresponding to the K' ', Cy-curves, we have the y, Cy-curves. These 

 curves pass through the common points y = 1> <?Y = 0, and y = 



The particular case when the value of m is equal to unity, which 

 leads to a linear relation between the function K' and the ion concentra- 

 tion, likewise yields a very simple relation between the equivalent con- 

 ductance and the specific conductance. In this case we may write our 

 equation : 



(35) or 



^o- 



It is obvious that the ratio ^ ^-, or what is proportional to it, the ratio 



Y 

 j , is now a linear function of the reciprocal of the specific conduct- 



