Assertion: `KMnO_(4)` has different equivalent wieghts in acid, neutral or alkaline medium.
Reason: In different, change in oxidation number shown by maganese is altogether different.

Options

A. If both assertion and reason are true and the reason is the correct explanation of assertion
B. If both assertion and reason are true and the reason is not the correct explanation of assertion
C. If assertion is false but reason is true
D. If assertion is true but the reason is false

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

**Assertion:** KMnO₄ has different equivalent weights in acid, neutral, or alkaline medium.

**Reason:** In different media, the change in oxidation number shown by manganese is altogether different.

### Step-by-Step Solution:

1. **Understanding KMnO₄:**
- KMnO₄ is potassium permanganate, a strong oxidizing agent. The manganese in KMnO₄ can exist in different oxidation states depending on the medium (acidic, neutral, or basic).

2. **Oxidation States in Different Media:**
- In acidic medium:
- KMnO₄ (Mn in +7 oxidation state) is reduced to Mn²⁺ (Mn in +2 oxidation state).
- Change in oxidation state: +7 to +2 (5 electrons).
- In neutral medium:
- KMnO₄ (Mn in +7 oxidation state) is reduced to MnO₂ (Mn in +4 oxidation state).
- Change in oxidation state: +7 to +4 (3 electrons).
- In basic medium:
- KMnO₄ (Mn in +7 oxidation state) is reduced to MnO₄²⁻ (Mn in +6 oxidation state).
- Change in oxidation state: +7 to +6 (1 electron).

3. **Calculating Equivalent Weight:**
- The equivalent weight of a substance is calculated using the formula:
\[ \text{Equivalent Weight} = \frac{\text{Molecular Weight}}{n} \]
where \( n \) is the number of electrons transferred in the reaction.
- For KMnO₄:
- In acidic medium: \( n = 5 \) (change from +7 to +2)
- In neutral medium: \( n = 3 \) (change from +7 to +4)
- In basic medium: \( n = 1 \) (change from +7 to +6)

4. **Conclusion:**
- Since the value of \( n \) changes based on the medium, the equivalent weight of KMnO₄ will also change in different media.
- Therefore, the assertion is true.

5. **Evaluating the Reason:**
- The reason states that the change in oxidation number of manganese is different in different media, which is indeed true.
- However, it does not fully explain why the equivalent weights are different. The assertion is correct, but the reason does not adequately explain the assertion.

### Final Answer:
- Both the assertion and reason are true, but the reason is not the correct explanation for the assertion.