Question

The value of $K_b$ for the hydrolysis reaction $B^{+}+H_{2}O\rightleftharpoons BOH+H^{+}$ is $1.0\times {10}^{-6}$. The hydrolysis constant of the salt is:

• A. ${10}^{-6}$
• B. ${10}^{-7}$
• C. ${10}^{-8}$
• D. ${10}^{-9}$

Answer 1

The correct option is C ${10}^{-8}$

Given a hydrolysis reaction:

$B^{+}+H_{2}O\leftrightharpoons BOH+H^{+}$

The expression for hydrolysis constant is as given below.
$K_H=\frac{K_w}{K_b}$
Substituting values in the above expression, we get
$K_H=\frac{K_w}{K_b}=\frac{{10}^{-14}}{{10}^{-6}}={10}^{-8}$

Hence, the hydrolysis constant of the salt is ${10}^{-8}$.