Equilibrium Question 247
Question: 0.5 M ammonium benzoate is hydrolysed to 0.25 percent, hence its hydrolysis constant is [MH CET 2004]
Options:
A) $ 2.5\times {10^{-5}} $
B) $ 1.5\times {10^{-4}} $
C) $ 3.125\times {10^{-6}} $
D) $ 6.25\times {10^{-4}} $
Show Answer
Answer:
Correct Answer: C
Solution:
$ C_6H_5COONH_4\to C_6H_5CO{O^{-}}+NH_4^{+} $
$ 0.5-\frac{.25}{100} $
$ \frac{.25}{100} $
$ \frac{.25}{100} $ According to Ostwald dilution law. $ K=\frac{{{\alpha }^{2}}C}{1-\alpha } $
$ ( \therefore \ \ \alpha =\frac{.25}{100} ) $
$ K={{\alpha }^{2}}C $
$ ( \because \ \ 1-\alpha =\text{Very small} ) $
$ K=\frac{.25}{100}\times \frac{.25}{100}\times .5 $ ; $ K=3.125\times {10^{-6}} $
