CONDUCTION PROCESS IN ELECTROLYTES 



31 



the purposes of graphical extrapolation it is preferable to employ some 

 function of the concentration which brings the point of zero concentra- 

 tion, to which the extrapolation must be carried, to one of the axes on the 

 plot. A convenient function which yields a simple type of curve is the 

 cube root of the concentration. Such plots for potassium chloride and 

 sodium chloride are shown in Figure 2. If the curves for potassium 

 chloride and sodium chloride are extrapolated, they yield for the limit- 

 ing value of the equivalent conductance values in the neighborhood of 

 130.0 and 108.9 respectively. The value obtained for A will, of course, 

 depend upon the extrapolation function employed. In another chapter 



I 



140 



\zo 



100 



60 



40 



20 



S 4.0 4S AO 3* ?.0 ZJS T.O f.5 0.0 



Log C. 



FIG. 1. Showing A as a Function of Log C for Aqueous Solutions at 18. 



various functions proposed for this purpose will be discussed more in 

 detail. For the present it will be sufficient to employ approximate values 

 for the purpose of comparing the behavior of different electrolytes. 



The equivalent conductance of hydrochloric acid is much greater than 

 that of the salts. The conductance curve, however, is similar in form 

 to that of the salts. That is, with decreasing concentration, the equiva- 

 lent conductance approaches a limiting value. In the case of hydro- 

 chloric acid this value is in the neighborhood of 380 at 18. We may 

 now ask the question: To what are the differences in the values of the 

 equivalent conductance of the different electrolytes due? Why, for ex- 

 ample, is the equivalent conductance of hydrochloric acid greater than 

 that of potassium chloride? Or, in other words, to what is the greater 



