The oxidation of oxalic acid by acidified `KMnO_4` becomes fast as the reaction progresses due to :

Options

A. Presence of `Mn^(+2)`
B. Presence of `SO_(4)^(2)`
C. Presence of `K^(+)`
D. Presence of `MnO_(4)^(-)`

Answer

To solve the question regarding the oxidation of oxalic acid by acidified KMnO₄ and why the reaction becomes faster as it progresses, we can break down the explanation into clear steps:

### Step-by-Step Solution:

1. **Understanding the Reaction**:
- The reaction involves oxalic acid (C₂H₂O₄) being oxidized by potassium permanganate (KMnO₄) in an acidic medium (usually sulfuric acid, H₂SO₄).
- The balanced chemical equation for this reaction shows that KMnO₄ is reduced to manganese(II) sulfate (MnSO₄) while oxalic acid is oxidized to carbon dioxide (CO₂).

2. **Formation of Products**:
- As the reaction proceeds, one of the key products formed is manganese(II) ions (Mn²⁺) from the reduction of permanganate ions (MnO₄⁻).
- The formation of Mn²⁺ is crucial as it plays a significant role in the reaction dynamics.

3. **Auto-Catalysis Concept**:
- Auto-catalysis occurs when one of the products of a reaction acts as a catalyst for that same reaction.
- In this case, the Mn²⁺ ions produced during the reaction serve as a catalyst, thereby accelerating the oxidation of oxalic acid.

4. **Increasing Reaction Rate**:
- As more Mn²⁺ ions are produced, they facilitate the oxidation of oxalic acid at a faster rate.
- This leads to an increase in the overall reaction speed as the concentration of the catalyst (Mn²⁺) increases with time.

5. **Conclusion**:
- Therefore, the reason the oxidation of oxalic acid by acidified KMnO₄ becomes faster as the reaction progresses is due to the auto-catalytic effect of the manganese(II) ions formed during the reaction.

### Final Answer:
The oxidation of oxalic acid by acidified KMnO₄ becomes fast as the reaction progresses due to the auto-catalysis by manganese(II) ions (Mn²⁺) formed during the reaction.

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