The product, which is not obtained during the electrolysis of brine solution is :

Solution

Chemistry ma’am · 4 steps

Write the two electrode reactions and see what is left in the solution: there is nothing to make HCl.

1. At the cathode. Water is reduced more easily than Na⁺, so hydrogen gas forms and the solution near the cathode turns basic: 2H₂O + 2e⁻ → H₂ + 2OH⁻.
2. At the anode. In concentrated brine, Cl⁻ is oxidised to chlorine gas because of the overpotential for oxygen evolution: 2Cl⁻ → Cl₂ + 2e⁻.

   2NaCl + 2H₂O → 2NaOH + H₂ + Cl₂

3. What stays behind. The Na⁺ ions are not discharged. They stay in solution with the OH⁻ formed at the cathode, so the solution becomes NaOH. The H⁺ and Cl⁻ needed for HCl are never present together, because hydrogen leaves as H₂ and chlorine leaves as Cl₂.
4. So. The products are NaOH, Cl₂ and H₂. HCl is not obtained, so the answer is (d).

The idea to keep. For electrolysis of aqueous salts, check which species is easier to discharge at each electrode, water or the ion. The ions that are not discharged stay in the solution and make the solution product.

Answer from the NTA final answer key. Solution by PrepWiser.