158 PROPERTIES OF ELECTRICALLY CONDUCTING SYSTEMS 



decreases slightly as the temperature increases. The value of K, how- 

 ever, is so small that this effect is scarcely appreciable. At concentra- 

 tions greater than 3.6 normal, the ionization increases with the tempera- 

 ture, and this increase is the greater the greater the value of m. In 

 general, the increased conductance due to increased ionization in these 

 regions is masked by the rapidly increasing effects of viscosity. In the 

 ' neighborhood of normal concentration the viscosity effect becomes suffi- 

 ciently great to overbalance the conductance increase due to increased 

 ionization and the conductance-temperature curves pass through a maxi- 

 mum in this region, after which they fall off very rapidly. Nevertheless, 

 it is to be noted that, in all cases for which measurements are available 

 at different temperatures in very concentrated solutions, the conductance 

 increases markedly with the temperature and this increase is the greater 

 the higher the concentration. In Table LVIII are given values of the 

 conductance of concentrated solutions of different salts in methylamine 

 and ethylamine at a series of temperatures. 13 



What is striking in these results is the high value of the temperature 

 coefficient at high concentration, as, for example, in solutions of silver 

 nitrate in methylamine at V = 0.2456. Between 33.5 and 15 

 the conductance increases 91 per cent or 4.92 per cent per degree. The 

 same holds true for solutions of silver nitrate in ethylamine, where the 

 conductance increases nearly 100 per cent between 33.5 and 15 

 at 0.4083 N, while, between 15 and 0, the conductance of solutions 

 of ethylammonium chloride increases 6.76 per cent per degree at 0.17 N. 

 It is true that the viscosity in these concentrated solutions must differ 

 greatly from that of the solvent and the viscosity may change much 

 more rapidly with the temperature in the case of the concentrated solu- 

 tions than in that of the more dilute solutions. Nevertheless, it appears 

 not improbable that the high value of the temperature coefficients of 

 concentrated solutions is in part due to the increased ionization at these 

 high concentrations. 



As the concentration decreases below 3.6 N, the ionization decreases 

 with increasing temperature. Those solutions for which m is less than 

 unity exhibit an increase in ionization throughout with decreasing con- 

 centration, while those solutions for which m is greater than unity exhibit 

 first a decrease and then an increase, so that the ionization curves pass 

 through minima in the neighborhood of 0.1 N. These minima are the 

 more pronounced the greater the value of m. In very dilute solutions, 

 again, the ionization curves approach one another, corresponding to the 

 fact that at low concentrations the ionization in all cases approaches unity. 



18 Fitzgerald, J. Phya. Chem. 16, 621 (1912). 



