Equilibrium Question 152
Question: The solubility product of $ BaSO_4 $ at $ 25{}^\circ C $ is $ 1.0\times {10^{-9}} $ . What would be the concentration of $ H_2SO_4 $ necessary to precipitate $ BaSO_4 $ from a solution of $ 0.01,M,B{a^{2+}} $ ions [RPMT 1999]
Options:
A) $ {10^{-9}} $
B) $ {10^{-8}} $
C) $ {10^{-7}} $
D) $ {10^{-6}} $
Show Answer
Answer:
Correct Answer: C
Solution:
$ BaSO_4 $ ⇌ $ \underset{0.01}{\mathop{\underset{(S),}{\mathop{B{a^{++}}}},}},+\underset{5}{\mathop{\underset{(S)}{\mathop{SO_4^{-,-}}},}}, $
$ K _{sp}=S^{2}=S\times S=0.01\times S $
$ {S _{(SO_4^{2-})}}=\frac{K _{sp}}{{S _{(B{a^{++}})}}}=\frac{1\times {10^{-9}}}{0.01}={10^{-7}} $ mole/litre
