224 Conductivity of Aqueous Solutions. Part VII. 



A comparison of the separate values of the ionization-constants for 

 nearly the same concentrations in tables 82 and 83 shows at each tem- 

 perature an entirely satisfactory agreement. Moreover, the mean of 

 the first series of values for ammonium hydroxide, which were obtained 

 with solutions prepared from a pure commercial aqua ammonia, will be 

 seen to be identical with the mean of the second series of values, which 

 with solutions prepared from a pure commercial aqua ammonia, will be 



84. FINAL VALUES OF THE EQUIVALENT CONDUCTANCE AND THEIR 

 VARIATION WITH THE CONCENTRATION AND TEMPERATURE. 



Final values of the equivalent conductance at round concentrations for 

 ammonium chloride and sodium acetate and for ammonium hydroxide and 

 acetic acid have been derived from those given in tables 80 to 83. 



This has been done in the case of the two salts at 306 with the help 

 of the function C(A A) = K(CA) n by first determining the values of 

 the three constants A , K, and n, by substituting the values of A at the 

 three widely different concentrations, and then calculating in the reverse 

 way the value of A for various round concentrations. In the case of 

 ammonium chloride at 18 and 218, however, since only two widely 

 different concentrations were investigated, the value of n was assumed 

 to be identical with that found for the very analogous salt potassium 

 chloride, namely 1.42 at 18 and 1.50 at 218. (At 18 and 25 the 

 measurements with the pure salt, without excess of ammonium hydroxide, 

 were alone utilized.) The values of A and of A so obtained are sum- 

 marized in Table 84. The values of n at 306 derived as just described 

 are 1.44 for ammonium chloride and 1.49 for sodium acetate. 



In the cases of ammonium hydroxide and acetic acid values for A 

 were first obtained indirectly by the relations : 



A (NH 4 OH) = A (NH 4 Cl) +A (N a OH) A (NaCl) 



A (HAc) = A (NaA ) + A (HCl) A (N a Cl) 



Most of the A -values for the substances on the right were taken from the 

 various parts of this publication. In the case of sodium hydroxide, how- 

 ever, no measurements exist at 306, and those at 218 are not suf- 

 ficiently accurate nor extensive. A -values for it were therefore derived 

 under the assumption that it lies at such a proportional distance between 

 the A -values for sodium chloride and hydrochloric acid at these tem- 

 peratures as is indicated by its position between them at the lower 

 temperatures of 18, 100, and 156. All these A -values are given in 

 the following table. Those for ammonium acetate which are needed in 

 the subsequent calculation of the hydrolysis of this salt are also included. 

 They were derived by combination of those for ammonium chloride, 



