Question

Choose the correct statement.

• A. Calcium and Magnesium metals are manufactured by electrolysis of aqueous solutions of their salts
• B. The oxo-anion \(ClO_3^-\) does not undergo disproportionation reaction
• C. Nitride ion \(N^{3-}\) cannot act as an oxidising agent
• D. In alkaline medium the reduction of \(MnO_4^-\) ion involves gain of 5 electrons

Hint:

An oxidising agent must gain electrons. Species already in lowest oxidation state (like \(N^{3-}\)) cannot be reduced further.

Answer 1

The Correct Option is C

Step 1: Analyse option (A).
Calcium and Magnesium are highly reactive metals and cannot be obtained from aqueous solutions because water gets reduced first.
They are obtained by electrolysis of molten salts, not aqueous solutions.
Hence, (A) is incorrect.

Step 2: Analyse option (B).
The ion \(ClO_3^-\) (chlorate) can undergo disproportionation under suitable conditions.
Thus, the statement that it does not undergo disproportionation is incorrect.

Step 3: Analyse option (C).
Nitride ion \(N^{3-}\) is already in its lowest oxidation state.
Since it cannot be reduced further, it cannot accept electrons.
Therefore, it cannot act as an oxidising agent.
Hence, (C) is correct.

Step 4: Analyse option (D).
In alkaline medium, \(MnO_4^-\) is reduced to \(MnO_2\), involving gain of 3 electrons, not 5.
So, (D) is incorrect.

Step 5: Conclusion.
Only option (C) satisfies the correct chemical reasoning.

Step 6: Final Answer.
\[ \boxed{\text{Nitride ion } N^{3-} \text{ cannot act as an oxidising agent}} \]