Question

The degree of hydrolysis of a salt of weak acid and a weak base in it's 0.1M solution is found to be 50%. If the molarity of the solution is 0.2M, the percentage hydrolysis of the salt should be:

• A. 100%
• B. 50%
• C. 25%
• D. none of these

Answer 1

Answer: (B)

50%

degree of hydrolysis of salt of weak acid and weak base is independent of concentration(molarity) of solution

Ex.

Suppose a weak acid and weak base salt $C{H}_{3}COON{H}_4$

$\underset{C(1-h)}{C{H}_{3}CO{O}^{-}}+\underset{C(1-h)}{N{H}_4^{+}+H_{2}O}\to \underset{Ch}{C{H}_{3}COOH}+\underset{Ch}{N{H}_{4}OH}$

According to law of mass action

$k_h=\frac{C^2{h}^2}{C^2(1-h^2)}=\frac{h^2}{1-h^2}$ (Independent on C)

Hence B is correct option