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

Step 1: Understanding the Question:
The question asks for the specific chemical species formed at the negative electrode (cathode) during the electrolysis of sodium chloride in its molten (liquid) state.
Step 2: Detailed Explanation:
In molten NaCl, the only ions present are \(\text{Na}^+\) and \(\text{Cl}^-\). There is no water present to compete for reduction or oxidation.
1. At the Cathode (Reduction):
The positive sodium ions (\(\text{Na}^+\)) migrate to the negative cathode, where they gain electrons to form neutral sodium metal.
\[ \text{Na}^+ + e^- \rightarrow \text{Na}(l) \]
2. At the Anode (Oxidation):
The negative chloride ions (\(\text{Cl}^-\)) migrate to the positive anode, where they lose electrons to form chlorine gas.
\[ 2\text{Cl}^- \rightarrow \text{Cl}_2(g) + 2e^- \]
Step 3: Final Answer:
Sodium metal is the product liberated at the cathode.