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 of the light purple color fading and disappearing when a dilute ferrous sulfate solution is added to an acidified permanganate solution, we can follow these steps:

### Step 1: Identify the Reactants
- The reactants in this reaction are dilute ferrous sulfate (FeSO4) and acidified potassium permanganate (KMnO4).

### Step 2: Understand the Role of KMnO4
- Potassium permanganate (KMnO4) is known to be a strong oxidizing agent. In an acidic medium, it can oxidize various substances.

### Step 3: Reaction Mechanism
- When KMnO4 is added to the ferrous sulfate solution, it reacts with the ferrous ions (Fe²⁺) present in FeSO4. The oxidation state of iron in ferrous sulfate is +2.

### Step 4: Oxidation of Ferrous Ion
- The KMnO4 oxidizes the ferrous ion (Fe²⁺) to ferric ion (Fe³⁺). The oxidation state of iron changes from +2 in FeSO4 to +3 in ferric sulfate (Fe₂(SO₄)₃).

### Step 5: Formation of Products
- The products of this reaction include ferric sulfate (Fe₂(SO₄)₃), potassium sulfate (K₂SO₄), manganese sulfate (MnSO₄), and water (H₂O).

### Step 6: Color Change Observation
- The light purple color of the permanganate solution fades and eventually disappears because the permanganate ions (MnO₄⁻), which impart the purple color, are reduced to manganese ions (Mn²⁺), which are nearly colorless in dilute solutions.

### Step 7: Conclusion
- The overall reaction can be summarized as:
\[ 2 KMnO_4 + 8 H_2SO_4 + 10 FeSO_4 \rightarrow 5 Fe_2(SO_4)_3 + K_2SO_4 + 2 MnSO_4 + 8 H_2O \]
- Therefore, the correct explanation for the observation is that KMnO4 acts as an oxidizing agent, oxidizing FeSO4 to Fe₂(SO₄)₃, leading to the disappearance of the purple color.