PURE SUBSTANCES, FUSED SALTS, SOLID ELECTROLYTES 355 



Jaeger and Kapma 6a have measured the specific conductance and the 

 densities of potassium nitrate, sodium nitrate, lithium nitrate, rubidium 

 nitrate, caesium nitrate, potassium fluoride, potassium chloride, potas- 

 sium bromide, potassium iodide, sodium molybdate, and sodium tung- 

 state over considerable temperature ranges. At a given temperature, the 

 equivalent conductance of the different salts is of the same order of 

 magnitude. For the nitrates the conductance increases in order from 

 caesium to lithium. For the potassium halide salts, the conductance is 

 smallest for the fluoride and greatest for the chloride, while that of the 

 iodide and bromide is intermediate between them. 



The conductance increases very nearly, although not quite, as a 

 linear function of the temperature. The temperature coefficients vary 

 appreciably, being greatest for potassium fluoride and smallest for 

 caesium nitrate. 



The conductance of mixtures of fused salts is very nearly a linear 

 function of the composition. In the following table are given values of 

 the conductance of mixtures of sodium and potassium nitrates at 450, 



together with the values of F and of -^. 7a It will be observed that as the 



r 



concentration changes the conductance varies continuously between that 

 of the two components. 



TABLE CXXXVII. 



CONDUCTANCE OF MIXTURES OF SODIUM AND POTASSIUM NITRATES AT 450. 



100 molar % KN0 3 

 0.973 

 55.03 

 60.2 

 0.915 



The fact that in the mixtures of fused salts the conductance is approxi- 

 mately a linear function of the composition shows that no considerable 

 reaction takes place on mixing. This indicates a high degree of ioniza- 

 tion of the fused electrolyte. 



In Table CXXXVIII are given values of the conductance of mixtures 

 of silver iodide and silver bromide at 550. 7 Here, again, the conduc- 



TABLE CXXXVIII. 

 CONDUCTANCES OF MIXTURES OF SILVER IODIDE AND SILVER BROMIDE. 



%AgBr 5 10 20 30 40 60 70 80 90 100 

 pi.... 2.36 2.40 2.39 2.41 2.43 2.50 2.64 2.67 2.68 2.84 3.00 



88 Jaeger and Kapma, Ztschr. f. Anorg. Chem. 113, 27 (1920). 



T Goodwin and Mailey, loc. cit. 



T Tubandt and Lorenz, Ztschr. f. phya, Chem. 87, 543 (1914). 



