2002 AIPMT EquilibriumSolubility Product Easy Question 9 of 10 in Solubility Product

Solubility of $MX_2$-type electrolytes is $0.5 \times 10^{-4}$ mole/lit. Then find out $K_{sp}$ of electrolytes : -

A $5 \times 10^{-12}$
B $25 \times 10^{-10}$
C $1 \times 10^{-13}$
D $5 \times 10^{-13}$

The answer is D.

Solution

$MX_2 \rightleftharpoons M^{2+} + 2X^-$. If the solubility is s, then $[M^{2+}] = s$ and $[X^-] = 2s$.
$K_{sp} = s(2s)^2 = 4s^3$
$s = 0.5 \times 10^{-4}$, so $s^3 = 0.125 \times 10^{-12} = 1.25 \times 10^{-13}$
$K_{sp} = 4 \times 1.25 \times 10^{-13} = 5 \times 10^{-13}$

Concept Ksp of MX2 type salt

Solubility Product in past papers

10 questions from this chapter have appeared across 10 exam years.