Question

Sodium sulphite (Na₂SO₃ ) and sodium hydrogen sulphite (NaHSO₃ ) are salts of sodium but sodium sulphite is called a normal salt and sodium hydrogen sulphite is called an acid salt. Why? 

Answer 1

Sodium hydrogen sulphite has replaceable hydrogen in its molecule so it is called an acid salt but sodium sulphite does not have, so it is called a normal salt.

NaHSO₃ ⇋  Na⁺ + HSO₃^-

HSO₃  ⇋  H⁺ + SO₃^2-