Equilibrium Question 192
Question: The solubility of $ PbCl_2 $ is [MP PMT 1995; DCE 1999]
Options:
A) $ \sqrt{K _{sp}} $
B) $ ^{3}\sqrt{K _{sp}} $
C) $ ^{3}\sqrt{\frac{K _{sp}}{4}} $
D) $ \sqrt{8K _{sp}} $
Show Answer
Answer:
Correct Answer: C
Solution:
$ PbCl_2 $ ⇌ $ \underset{S}{\mathop{P{b^{2+}}}},+\underset{S}{\mathop{2C{l^{-}}}}, $
$ K _{sp} $ of $ PbCl_2=[P{b^{2+}}]\times {{[C{l^{-}}]}^{2}} $ ; $ K _{sp}=S\times {{(2S)}^{2}} $
$ K _{sp}=S\times 4S^{2} $
$ =4S^{3} $ ; $ S^{3}=\frac{K _{sp}}{4} $ ; $ S=\sqrt[3]{\frac{K _{sp}}{4}} $
