Equilibrium Question 218
Question: Solubility product for salt $ AB_2 $ is $ 4\times {10^{-12}} $ . Calculate solubility [RPET 2003]
Options:
A) $ 1\times {10^{-3}}gmmol,/,litre $
B) $ 1\times {10^{-5}}gmmol,/,litre $
C) $ 1\times {10^{-4}}gmmol,/,litre $
D) $ 1\times {10^{-2}}gmmol,/,litre $
Show Answer
Answer:
Correct Answer: C
Solution:
$ AB_2 $ ⇌ $ \underset{(S),}{\mathop{{A^{2+}}}},+\underset{{{(2S)}^{2}}}{\mathop{2{B^{-}}}}, $
$ K _{sp}=4S^{3} $
$ S=\sqrt[3]{\frac{K _{sp}}{4}}=\sqrt[3]{\frac{4\times {10^{-12}}}{4}} $
$ =1\times {10^{-4}}gm.,mol/litre $
