Question

A solution contains 0.01 M Zn²⁺ and Cu²⁺ ions. It is saturated by passing H₂S gas in the solution. The solubility products of ZnS and CuS are 3.0 × 10^-22 and 8.0 × 10^-36 respectively. Which of the following is true? K₁ = 10^-7 , K₂ = 10^-14 , [H₂S, aq]saturated = 0.1 M

(A) ZnS will precipitate

(B) CuS will precipitate

(C) Both ZnS and CuS will precipitate

(D) Both Zn²⁺ and Cu²⁺ will remain in the solution

Answer 1

Correct option  (B) CuS will precipitate

Explanation:

Only the ionic product of CuS exceeds its K_sp and hence, it is precipitated.