Chemical and Ionic Equilibrium 2 Question 16
16. $\mathrm{H} X$ is a weak acid $\left(K_{a}=10^{-5}\right)$. It forms a salt $\mathrm{Na} X(0.1 \mathrm{M})$ on reacting with caustic soda. The degree of hydrolysis of $\mathrm{Na} X$ is
$(2004,1 \mathrm{M})$
(a) $0.01 %$
(b) $0.0001 %$
(c) $0.1 %$
(d) $0.5 %$
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Solution:
- $K_{h}\left(X^{-}\right)=\frac{K_{w}}{K_{a}}=\frac{10^{-14}}{10^{-5}}=10^{-9} \Rightarrow \alpha=\sqrt{\frac{K_{h}}{C}}=\sqrt{\frac{10^{-9}}{0.10}}=10^{-4}$
$%$ hydrolysis $=100 \alpha=0.01$
