Question

What will be the $pH$ and $\%\alpha$ (degree of hydrolysis) respectively for the salt of weak acid and weak base $\left(BA\right)$ of $0.1M$ concentration?
Given : $K_a$ for $HA={10}^{-6}$ and $K_b$ for $BOH={10}^{-6}$

• A. $5,1\%$
• B. $7,10\%$
• C. $9,0.01\%$
• D. $7,0.01\%$

Answer 1

The correct option is B $7,10\%$

$\because pH=\frac{1}{2}p{K}_w+\frac{1}{2}p{K}_a-\frac{1}{2}p{K}_b=7\text{and}\alpha =\sqrt{\frac{K_w}{K_a{K}_b}}=\sqrt{\frac{{10}^{-14}}{{10}^{-12}}}=0.1\text{Percentage of}\alpha =10\%$