342 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



given solvent at a given temperature, the logarithm of the equivalent con- 

 ductance is a linear function of the cube root of the concentration and 

 Ghosh's theory may be readily tested by plotting the experimentally 

 determined values of log A against those of C 1/3 . If the equation is 

 applicable, the experimental points should lie upon a straight line from 

 which the values of A and p may be determined. If the equation is not 

 applicable, the experimental points will evidently show a systematic 

 deviation from a straight line. 



In Figure 61 are shown the curves for potassium chloride in water and 

 for tetraethylammonium iodide in epichlorhydrin. It is evident from 

 the figure that the experimental points lie upon a curve concave toward 

 the axis of concentrations at low concentrations and convex toward this 

 axis at higher concentrations, with an inflection point between. The 

 experimental points show a systematic deviation from a linear relation 

 and Ghosh's equation therefore is not applicable. In Table CXXXIII 

 the observed and calculated conductance values are compared. 



TABLE CXXXIII. 



COMPARISON OF OBSERVED AND CALCULATED VALUES OF A FOR KC1 

 IN WATER AT 18. 



A =: 132.06 p== 3.620 X 10 3 !T=:291 D = 81 

 V 5X10 4 2X10 4 10 4 5X10 3 2X10 3 10 3 5X10 2 



Acaic 130.80 130.35 129.90 129.35 128.40 127.47 126.30 



A obs ' 129.51 129.32 129.00 128.70 128.04 127.27 126.24 



Aobs'-caic. ... 1.39 1.03 0.90 0.45 0.36 0.20 0.06 



V 2X10 2 10 2 50 20 10 5 2 1 



A C aic 124.31 122.37 119.97 116.9 112.1 107.4 99.7 92.7 



A ob8 126.24 122.37 119.90 115.6 111.8 107.5 101.3 96.5 



Aobs,caic. +0.03 0.00 0.07 0.3 0.3 0.1 +1.6 +3.8 



The experimental values have a relative precision not less than 0.05 

 per cent. It is evident, from the table, that the theoretical values deviate 

 from the experimental values far in excess of any conceivable experimen- 

 tal error, except at a few points in the immediate neighborhood of the 

 inflection point, which is at about 0.01 normal. As may be seen from 

 the curve for epichlorhydrin, the deviations in this solvent are much 

 greater than in water. It is to be noted, too, that the experimental points 

 again lie upon a curve which is of the same type as that of potassium 

 chloride in water; that is, the curve is concave toward the axis of concen- 

 tration at low concentrations and convex toward this axis at high con- 



