Question

The solubility product $(K_{sp} : mol^3 \, dm^{-9})$ of $MX_2$ at $298\,K$
based on the information available the given concentration cell is (take $ 2.303 \times R \times 298/F = 0.059 V$)

• A. $ 1 \times 10^{-15} $
• B. $ 4 \times 10^{-15} $
• C. $ 1 \times 10^{-12} $
• D. $ 4 \times 10^{-12} $

Answer 1

Answer: (B)

The solubility equilibrium for $MX_2$ is
$MX_2 (s) \rightleftharpoons M^{2+} (aq) + 2X^- (aq)$
Solubility product, $K_{sp}=][M^{2+}][X^-]^2$
$= 10^{-5} \times (2 \times 10^{-5})^2 =4 \times 10^{-15}$
$[\because $ In saturated solution of $MX_2,[X^-]=2[M^{2+}]]$