JEE · NEET Previous Year Question

$H_{2}S$ is passed into one ${\text{dm}}^3$ of a solution containing 0.1 mole of ${\text{Zn}}^{2+}$ and 0.01 mole of ${\text{Cu}}^{2+}$ till the sulphide ion concentration reaches $8.1\times {10}^{-19}$ moles. Which one of the following statements is true? [ $K_{\text{sp}}$ of $\text{ZnS}$ and $\text{CuS}$ are $3\times {10}^{-22}$ and $8\times {10}^{-36}$ respectively]

Topic: JEE PYQ

Answer: B. Full step-by-step solution below.