Equilibrium Ques 93

93. Solubility of $M X_2$-type eletrolytes is $0.5 \times 10^{-4}$ $mol /$ lit, then find out $K _{s p}$ of electrolytes

[2002]

(a) $5 \times 10^{-12}$

(b) $25 \times 10^{-10}$

(c) $1 \times 10^{-13}$

(d) $5 \times 10^{-13}$

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Answer:

Correct Answer: 93.(d)

Solution:

  1. (d) Given $s=0.5 \times 10^{-4}$ $ moles / L$

$[M X_2 \rightleftharpoons M^{2+}+2 X]$

$\because$ For $M X_2, K _{s p}=s \times(2 s)^{2}=4 s^{3}$

$K _{s p}=4 \times(0.5 \times 10^{-4})^{3}=4 \times 0.125 \times 10^{-12}$

$=0.5 \times 10^{-12}=5 \times 10^{-13}$