Question

Which of the following will supress the ionisation of acetic acid in aqueous solution?

• A. $NaCl$
• B. $HCI$
• C. $KCI$
• D. Unpredicatble

Answer 1

The correct option is B $HCI$

Adding a common ion prevents the weak acid or weak base from ionizing as much as it would without the added common ion. The common ion effect suppresses the ionization of a weak acid by adding more of an ion that is a product of this equilibrium.

So addition of $C{H}_{3}COONa$ to $C{H}_{3}COOH$ increases the $pH$ of solution but addition of $N{H}_{4}Cl$ to $N{H}_{4}OH$ decreases the $pH$ of solution.

Here, the addition of $HCl$ acid will suppress the ionisation of acetic acid.