Question

During the electrolysis of aqueous sodium chloride, the product obtained at the anode is

• A. \(\text{H}_2(g)\)
• B. \(\text{Cl}_2(g)\)
• C. \(\text{Na}(s)\)
• D. \(\text{O}_2(g)\)

Hint:

In electrolysis of brine: Anode → \(\text{Cl}_2\), Cathode → \(\text{H}_2\), Solution → \(\text{NaOH}\).

Answer 1

The Correct Option is B

Step 1: Understand electrolysis of brine.
Aqueous sodium chloride solution (brine) undergoes electrolysis, producing different products at the anode and cathode.

Step 2: Anodic reaction.
At the anode, oxidation occurs. Chloride ions lose electrons to form chlorine gas: \[ 2\text{Cl}^- \rightarrow \text{Cl}_2(g) + 2e^- \]

Step 3: Why oxygen is not formed.
Although water can also be oxidized, chloride ions are preferentially oxidized due to lower discharge potential.

Step 4: Conclusion.
Chlorine gas is liberated at the anode during electrolysis of aqueous sodium chloride.