Question

A solution contains 0.1 M Cl^– and 0.001 M CrO₄^2–. If solid AgNO₃ is gradually added to this solution which will precipitate first, AgCl or Ag₂CrO₄ ? Assume that the addition causes no change in volume. Given K_sp(AgCl)= 1.6 × 10^–10 M² and K_sp(Ag2CrO4) = 1.79 × 10^–12 M³. What % of Cl^– remains in solution when CrO₄^2– starts precipitating ?

Answer 1

Ag⁺ ion concentration required for precipitation

AgCl will precipitate first because it requires low concentration of Ag⁺ . Remaining concentration of Cl^– when Ag₂CrO₄ starts precipitating