Question

0.10 mol sample of AgNO₃ is dissolved in one litre of 2.00 M NH₃. Is it possible AgCl(s) form the solution by adding 0.010 mol of NaCl ? ( K_sp(AgCl) = 1.8 × 10^–10, K_{f[Ag(NH3)2⁺]} = 1.6 × 10⁷)

Answer 1

It is assumed that all Ag⁺ ions have been complex and only x amount is left

 x = 1.93 × 10^–9 M = [Ag⁺] undisolved 

[Cl^–] = 1.0 × 10^–2 M 

∴ [Ag⁺] [Cl^–] = 1.93 × 10^–9 × 1.0 × 10^–2 = 1.93 × 10^–11 < 1.8 × 10^–10 [K_sp(AgCl)] 

Hence, AgCl (s) will not precipitate.