FORM OF THE CONDUCTANCE FUNCTION 



99 



is shown in Figure 14, in which values of the mass-action function K' 

 are plotted against those of the concentration. The form of this function 

 is entirely different from that which has been found to hold in solutions 

 in non-aqueous solvents and it is obvious, moreover, that the function is 

 a comparatively complex one. At higher concentrations, and practically 

 down to 1.5 X 10" 4 normal, the K', C-curv is everywhere concave 

 toward the axis of concentrations. At this low concentration, however, 

 the curve changes its form, and approaches a value asymptotic to a line 

 parallel to the axis of concentrations. In order to establish the mass- 

 action law as a consequence of experimental observations it must be 



Concentration X 



FIG. 14. Showing Variation of K' with Concentration for Aqueous Solutions of 

 KC1 at 18 According to Washburn. 



shown that, over a measurable concentration interval, points on the curve 

 necessarily lie upon a horizontal straight line. As this has not been 

 done, it is evident that Washburn's conclusions remain in doubt. 



The manner in which the curve for the mass-action function ap- 

 proaches the axis depends upon the value of the constant m in the 

 general equation. For values of m greater than unity, the curve ap- 

 proaches the axis asymptotic to a line parallel to the axis of concen- 

 trations; while for values of m less than unity, it approaches the axis 

 asymptotic to the axis of K' . In the case of water, therefore, for which 

 the value of m appears to be less than unity, we should expect that the 

 K! curve would be everywhere concave toward the axis of concentrations. 



