Question

Which of the following is an acidic salt?

• A. $N{a}_{2}S{O}_4$
• B. $NaHS{O}_3$
• C. $N{a}_{2}S{O}_3$
• D. $K_{2}S{O}_4$

Answer 1

Answer: (B)

$NaHS{O}_3$

Here,

$N{a}_{2}S{O}_4$ and $K_{2}S{O}_4$ are salts formed by the reaction of the strong acid and strong base and hence they are chemically neutral salts, having pH 7.

When $NaHS{O}_3$ (Sodium bisulphite) salt is added to water and its solution is prepared, it dissociates in the solution as following ions -

$NaHS{O}_3\to N{a}^{+}+HS{O}_3^{-}$

$HS{O}_3^{-}+H_{2}O\to H_3{O}^{+}+S{O}_3^{2-}$

Here, $H_3{O}^{+}$ (hydronium ion) results in the acidic conditions of the solution and hence it is an acidic salt (since it produces acidic conditions).

$N{a}_{2}S{O}_3$ is a basic salt as it is formed by the combination strong base and weak acid.

Since $NaHS{O}_3$ is the acidic salt, the correct answer is option (B).