Question

Two statements are given below: Statement I: Molten NaCl is electrolysed using Pt electrodes. \( Cl_2 \) is liberated at the anode. 
Statement II: Aqueous CuSO\(_4\) is electrolysed using Pt electrodes. \( O_2 \) is liberated at the cathode. The correct answer is:

• A. Both statement I and II are correct
• B. Both statement I and II are not correct
• C. Statement I is correct but statement II is not correct
• D. Statement I is not correct but statement II is correct

Hint:

During electrolysis of molten NaCl, chlorine gas is liberated at the anode. In aqueous CuSO\(_4\) electrolysis with platinum electrodes, oxygen is released at the anode, not at the cathode.

Answer 1

The Correct Option is C

Step 1: Understanding Electrolysis of Molten NaCl 
- When molten sodium chloride (\( NaCl \)) is electrolysed using platinum electrodes, it undergoes the following reactions:
- At the cathode (\( - \)): \( Na^+ + e^- \rightarrow Na \) (Sodium metal is deposited)
- At the anode (\( + \)): \( 2Cl^- \rightarrow Cl_2 + 2e^- \) (Chlorine gas is liberated)
- Therefore, Statement I is correct since \( Cl_2 \) is indeed liberated at the anode.
Step 2: Understanding Electrolysis of Aqueous CuSO\(_4\) 
- When aqueous copper sulfate (\( CuSO_4 \)) is electrolysed using platinum electrodes:
- At the cathode: \( Cu^{2+} + 2e^- \rightarrow Cu \) (Copper is deposited)
- At the anode: \( 2H_2O \rightarrow O_2 + 4H^+ + 4e^- \) (Oxygen gas is liberated)
- However, the oxygen gas is liberated at the anode, not at the cathode, making Statement II incorrect.
Step 3: Evaluating the Given Options 
- Option (1): Incorrect, because Statement II is incorrect.
- Option (2): Incorrect, as Statement I is correct.
- Option (3): Correct, as Statement I is correct, and Statement II is incorrect.
- Option (4): Incorrect, as Statement I is correct.
Thus, the correct answer is 

Option (3).