Which do not decolourise `KMnO_(4)` in aqueous solution?

Options

A. `C_(2)O_(4)^(2-)`
B. `HSO_(3)^(-)`
C. `CO_(3)^(-)`
D. `SO_(3)^(-)`

Explanation

To determine which species do not decolorize KMnO₄ in aqueous solution, we need to analyze the behavior of KMnO₄ as an oxidizing agent and the nature of the ions involved.

### Step-by-Step Solution:

1. **Understanding KMnO₄**:
- KMnO₄ (Potassium permanganate) is known to be a powerful oxidizing agent. It can oxidize various substances in different media (neutral, acidic, and alkaline).

2. **Identifying the Species**:
- The question asks which species do not decolorize KMnO₄. Common ions that are tested against KMnO₄ include oxalate (C₂O₄²⁻), bisulfite (HSO₃⁻), carbonate (CO₃²⁻), and sulfite (SO₃²⁻).

3. **Reactions with KMnO₄**:
- KMnO₄ can decolorize in the presence of certain ions:
- **C₂O₄²⁻ (Oxalate)**: Decolorizes KMnO₄.
- **HSO₃⁻ (Bisulfite)**: Decolorizes KMnO₄.
- **SO₃²⁻ (Sulfite)**: Decolorizes KMnO₄.
- **CO₃²⁻ (Carbonate)**: Does NOT decolorize KMnO₄.

4. **Reason for Non-decolorization**:
- The carbonate ion (CO₃²⁻) does not decolorize KMnO₄ because it is insoluble in aqueous solution. The reason for its insolubility is that the ion-dipole attraction forces in the solution are not sufficient to overcome the bond between the metal cation and the carbonate ion.

5. **Conclusion**:
- Therefore, the species that does not decolorize KMnO₄ in aqueous solution is **CO₃²⁻ (Carbonate ion)**.

### Final Answer:
The species that does not decolorize KMnO₄ in aqueous solution is **CO₃²⁻ (Carbonate ion)**.

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