Question

Which among the following is correct for electrolysis of brine solution?

Options

• O₂ gas is liberated at cathode

• Sodium metal is collected at anode

• H₂ gas is liberated at cathode

• Cl₂ gas is liberated at cathode

Answer 1

H₂ gas is liberated at cathode

Explanation:

In electrolysis of brine solution, H₂ gas is liberated at cathode. The solution contains four ions Na⁺, Cl^⊖, H⁺ and OH ions. There occurs a race amongst them for their discharge at their respective electrodes.

Following electrode reactions are possible:

Cathode- \[\ce{2H2O(l) + 2e- -> H2(g) + 2\bar{\text{O}}H(aq)}\]

Anode- \[\ce{2Cl- (aq) -> Cl2(g) + 2e-}\]

In this electrolysis, H₂ at cathode and Cl₂ at anode are given off.