THE CONDUCTANCE OF SOLUTIONS VISCOSITIES 123 



of water up to 156, we may assume, in the absence of experimental 

 data, that it remains proportional at higher temperatures. In order, 

 therefore, to compare the conductance of the different ions with the 

 fluidity of water, we may compare the conductance of these ions with 

 that of the acetate ion whose values are known up to 306. The ratio 

 of the conductances of the various ions to that of the acetate ion is given 

 in Table XLV. 16 



TABLE XLV. 



INFLUENCE OF TEMPERATURE ON THE CONDUCTANCE OF VARIOUS IONS 

 RELATIVE TO THAT OF THE ACETATE ION. 



Ion Conductance at temperatures: 



0.0 18 25 50 75 100 128 156 218 306 



K + 1.99 1.87 1.83 1.72 1.66 1.58 1.54 1.50 1.32 1.18 



Na + 1.28 1.26 1.25 1.22 1.20 1.19 1.19 1.18 1.15 1.11 



NH 4 + .... 1.98 1.86 1.83 1.72 1.66 1.59 1.55 1.52 1.37 1.30 



Ag + 1.62 1.57 1.54 1.51 1.49 1.45 1.43 1.42 1.29 .. 



Cl- 2.02 1.89 1.85 1.73 1.67 1.59 1.54 1.51 1.32 1.18 



N0 3 - 1.99 1.78 1.73 1.55 1.46 1.37 1.30 1.25 1.21 .. 



H+ 11.82 9.08 8.58 6.95 5.88 4.95 4.23 3.68 2.79 1.82 



OH- 5.17 4.95 4.71 4.24 3.75 3.38 3.07 2.81 2.08 1.62 



In determining the conductance of the various ions, it is of course 

 necessary to assume values for the transference numbers of one pair of 

 ions. In the case of potassium chloride, the transference number is very 

 nearly 0.5 and at higher temperatures it appears to approach this value 

 as a limit. It has been assumed, therefore, that at temperatures above 

 100 the transference number of the potassium and chloride ions is 0.5. 

 This assumption, moreover, is justified by the fact that, as the tem- 

 perature increases, the transference numbers of all ions appear to 

 approach one another. In the above table the ionic conductances at 

 the higher temperatures are based upon this assumption. 



The relation between the ionic conductances and the temperature is 

 shown in Figure 21, where the conductances relative to the acetate ion are 

 plotted as ordinates and the temperatures as abscissas. Since the con- 

 ductance of the acetate ion is proportional to the fluidity of the solvent, 

 it follows that the ordinates will be proportional to the ratio of the ionic 

 conductances to the fluidity of the solvent. On examining the figure, 

 it will be seen that the greater the value of the conductance of an ion, 

 the less does the conductance increase as the temperature increases. 



A i 



That is, the ratio - decreases with increasing temperature and de- 



ac 



"Kraus, loc. cit. 



