Note 432 — Chapter XII · THE COPPER AND SILVER GROUPS (Continued).—THE THEORY OF COMPLEX IONS

We may consider the salt to be ionized to about the same extent as ammonium or potassium nitrate in 0.05 molar solutions, or, approximately, 87%. If we call x the concentration of silver-ion, formed by the decomposition of the silver-ammonium-ion, then 2 x is the concentration of the free ammonia, and (0.05 × 0.87 − x) is the concentration of the complex ion. Since x is a small number in comparison with 0.0435, we may write, with sufficient accuracy for our purposes,

[NH₃]² × [Ag⁺] / [(NH₃)₂Ag⁺] = (2 x)² × x / 0.0435 = 6.8E−8.

Then, x = [Ag⁺] = 0.0009.