Question

Which of the following salt undergoes hydrolysis?
(A) $C{{H}_{3}}COOK$
(B) $NaN{{O}_{3}}$
(C) $KCl$
(D) ${{K}_{2}}S{{O}_{4}}$

Answer 1

Those salts undergo cationic hydrolysis which are composed of strong acid and weak base. Check each given species whether it is produced from strong acid and weak base or not.

Complete answer:
Salts which are made from strong acid and weak base undergo cationic hydrolysis. Cationic hydrolysis of such salts leads to the formation of acidic solutions. Strong acids are those acids which undergo complete dissociation in the aqueous solution while weak acids are those acids which undergo partial dissociation (not fully dissociated) in the aqueous solution. Similarly, strong bases are those bases which undergo complete dissociation in the aqueous solution while weak bases are those bases which undergo partial dissociation (not fully dissociated) in the aqueous solution.
Potassium acetate $(C{{H}_{3}}COOK)$ is a salt of weak acid $(C{{H}_{3}}COOH)$ and strong base $\left( NaOH \right)$ as shown below.
$C{{H}_{3}}COOK+{{H}_{_{2}}}OC{{H}_{3}}COOH+NaOH$ this process undergoes hydrolysis.
The salt of strong acid and strong base does not undergo hydrolysis. So, only $C{{H}_{3}}COOK~$ (strong base + weak acid) will undergo hydrolysis in water and give a basic solution.

Note:
Do not get confused between cationic hydrolysis and anionic hydrolysis. Cationic hydrolysis shown by salts consisting of strong acid and weak base components. Such salts produce acidic solutions. On the other hand anionic hydrolysis shown by salts consists of strong base and weak acid. Such salts produce basic solutions.