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:

Always distinguish between molten and aqueous electrolysis. In aqueous \( NaCl \) electrolysis, hydrogen gas (\( H_2 \)) is obtained at the cathode instead of sodium metal because water is easier to reduce than sodium ions.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify the substance formed at the negative electrode (cathode) during the electrolysis of liquid (molten) sodium chloride.

Step 3: Detailed Explanation:
1. Components: Molten \( NaCl \) contains only \( Na^+ \) and \( Cl^- \) ions. Unlike aqueous \( NaCl \), there is no water to compete for reduction or oxidation.
2. At the Cathode (Negative Electrode):
Reduction occurs here. The positive \( Na^+ \) ions move toward the cathode, where they gain electrons.
\[ Na^+ + e^- \rightarrow Na(l) \] Sodium metal is deposited or formed at the cathode.
3. At the Anode (Positive Electrode):
Oxidation occurs here. The negative \( Cl^- \) ions move toward the anode, where they lose electrons.
\[ 2Cl^- \rightarrow Cl_2(g) + 2e^- \] Chlorine gas is evolved at the anode.

Step 4: Final Answer:
The product at the cathode during the electrolysis of molten \( NaCl \) is sodium (Na) metal.