Question

Assertion (A): If an aqueous solution of NaCl is electrolysed, the product obtained at cathode is H₂ gas and not Na.

Reason (R): Gases are liberated faster than the metals.

Options

• If both A and R are true, and R is the correct explanation of A.

• If both A and R are true, and R is the correct explanation of A.

• If A is true, but R is false.

• If both A and R are false.

Answer 1

If A is true, but R is false.

Explanation:

The assertion is true because during the electrolysis of aqueous NaCl, water has a higher standard reduction potential than sodium ions (Na⁺), meaning hydrogen ions (H⁺) are preferentially reduced at the cathode to produce H₂ gas. This reason is false because preferential discharge depends on thermodynamic reduction potentials and kinetics, not on gases being universally liberated faster than metals. Under different conditions (like using a mercury cathode), a metal can easily deposit instead of a gas.