A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?

Options

A. `KMnO_(4)` is an oxidising agent, it oxidises `FeSO_(4)`
B. `FeSO_(4)` acts as an oxidising agent and oxidises `KMnO_(4)`
C. The colour disappears due to dilution, no reaction is involved
D. `KMnO_(4)` is an unstable compound and decomposes in the presence of `FeSO_(4)` to a colourless compound

Explanation

To explain the observation that the light purple color of the acidified permanganate solution fades and finally disappears upon the addition of dilute ferrous sulfate solution, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The two main reactants in this reaction are potassium permanganate (KMnO4) in an acidified solution (using dilute sulfuric acid, H2SO4) and ferrous sulfate (FeSO4).

2. **Understand the Role of KMnO4**:
- Potassium permanganate is a strong oxidizing agent. In acidic medium, it has manganese in the +7 oxidation state (MnO4^-).

3. **Oxidation-Reduction Reaction**:
- When ferrous sulfate (FeSO4) is added to the permanganate solution, the ferrous ion (Fe^2+) is oxidized to ferric ion (Fe^3+), while the permanganate ion (MnO4^-) is reduced from +7 to +2 oxidation state (Mn^2+).

4. **Write the Balanced Chemical Equation**:
- The balanced equation for the reaction is:
\[ 2 KMnO4 + 10 FeSO4 + 8 H2SO4 \rightarrow K2SO4 + 2 MnSO4 + 5 Fe2(SO4)3 + 8 H2O \]

5. **Color Change Explanation**:
- The initial purple color of the KMnO4 solution is due to the MnO4^- ions. As the reaction proceeds, these ions are reduced to Mn^2+, which is colorless in dilute solution. This leads to the fading and eventual disappearance of the purple color.

6. **Conclusion**:
- The correct explanation for the observation is that KMnO4 acts as an oxidizing agent, oxidizing FeSO4 to Fe2(SO4)3, while itself being reduced, which results in the loss of color.