The Elements of Qualitative Chemical Analysis, vol. 1, parts 1 and 2. / With Special Consideration of the Application of the Laws of Equilibrium and of the Modern Theories of Solution.

by Julius Stieglitz

[433] Kohlrausch and Holborn, loc. cit., p. 202.

[434] The dilution of the silver-ammonium nitrate (10 c.c. to 11 c.c.) and the decrease in ionization due to the added salt reduce the concentration of silver-ion from 0.0009 to 0.00085. [Ag(NH₃)₂⁺] = (0.05 × 10 / 11) × 0.8 = 0.0364 and 4 x³ = 6.8E−8 × 0.0364 (see footnote, p. [220]). Then x = [Ag⁺] = 0.00085.

[435] Thiel (cf. Bodländer and Fittig, loc. cit.). The solubility given in the table at the end of the laboratory manual refers to 18°. The constant for the complex ion was determined at 25°.

[436] The combined concentration of the salts is 0.055 and their degree of ionization may be taken as 87%, the same as the degree of ionization of 0.05 to 0.06 molar KNO₃. Then [Cl⁻] = (0.1 × 1 / 11) × 0.87 = 0.008. [Ag(NH₃)₂⁺] = (0.05 × 10 / 11) × 0.87 = 0.04 and x = [Ag⁺] = 0.00089 (see the method of calculation in the footnote, p. [220]).

[437] The strong solution of ammonia is used in order to avoid unnecessary dilution, and in the experiment, described below, the dilution of the liquids by the added ammonia is considered negligible.

[438] The following solubilities have been determined at 25°:

[Ag+] × [Cl−] = 2E−10;	[Ag+] = 1.4E−5.
[Ag+] × [I−] = 1E−15;	[Ag+] = 1E−8.
[Ag+]2 × [S2−] = 4E−50;	[Ag+] = 4.3E−17.

[439] 100 c.c. molar ammonia dissolves at 25° only 0.6 milligram of silver iodide (Bodländer, loc. cit., p. 606).

[440] Fresenius, Qualitative Analysis, p. 378.

[441] In regard to Cu(NH₃)₄²⁺ see Locke and Forssall, Am. Chem. J., 31, 268, 297 (1904), and Dawson, J. Chem. Soc. (London), 89, 1674 (1906).