Question

In the electrolysis of molten NaCl, the product obtained at the cathode is:

• A. Cl gas
• B. Na metal
• C. NaOH
• D. H gas

Hint:

In electrolysis of molten salts, only the ions of the salt participate in the reaction since water is absent. Cathode (reduction): metal ion gains electrons → metal formed. Example: \( \text{Na}^+ + e^- \rightarrow \text{Na} \).

Answer 1

The Correct Option is B

Concept: Electrolysis is the process in which electrical energy is used to drive a non-spontaneous chemical reaction.
• Cathode: Reduction occurs (gain of electrons)
• Anode: Oxidation occurs (loss of electrons) In molten NaCl, only \( \text{Na}^+ \) and \( \text{Cl}^- \) ions are present because there is no water.

Step 1: Identify the ions present in molten NaCl. \[ \text{NaCl (molten)} \rightarrow \text{Na}^+ + \text{Cl}^- \]

Step 2: Reaction occurring at the cathode (reduction). At the cathode, sodium ions gain electrons: \[ \text{Na}^+ + e^- \rightarrow \text{Na} \] Thus, sodium metal is deposited at the cathode.

Step 3: Reaction occurring at the anode. Chloride ions lose electrons: \[ 2\text{Cl}^- \rightarrow \text{Cl}_2 + 2e^- \] This produces chlorine gas at the anode. Therefore, the product formed at the cathode during electrolysis of molten NaCl is \[ \boxed{\text{Na metal}} \]