Assertion :- `MnO_(4)^(-)` is always reduced to `Mn^(+2)`.
Reason :- Decrease in oxidation number or gaining of electron means oxidation.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion.
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion.
C. If Assertion is True but the Reason is False.
D. If both Assertion & Reason are False.

Answer

To analyze the given statements regarding the assertion and reason, we will break down the solution into clear steps:

### Step 1: Analyze the Assertion
The assertion states that `MnO4^(-)` is always reduced to `Mn^(+2)`.

1. **Determine the oxidation state of Mn in `MnO4^(-)`**:
- Let the oxidation state of Mn be \( x \).
- The formula for `MnO4^(-)` can be set up as:
\[ x + 4(-2) = -1 \]
- Simplifying this gives:
\[ x - 8 = -1 \implies x = +7 \]
- Therefore, the oxidation state of Mn in `MnO4^(-)` is +7.

2. **Determine the oxidation state of Mn in `Mn^(+2)`**:
- The oxidation state of Mn in `Mn^(+2)` is +2.

3. **Evaluate the reduction process**:
- The change in oxidation state from +7 to +2 indicates a reduction because the oxidation state is decreasing.

4. **Conclusion about the assertion**:
- While `MnO4^(-)` can be reduced to `Mn^(+2)` under specific conditions (like in acidic medium), it is not always the case that it will be reduced to +2. It can also be reduced to other oxidation states (like +4 or +3) depending on the reaction conditions.
- Therefore, the assertion is **false**.

### Step 2: Analyze the Reason
The reason states that a decrease in oxidation number or gaining of electrons means oxidation.

1. **Understanding oxidation and reduction**:
- **Oxidation** is defined as the increase in oxidation state or the loss of electrons.
- **Reduction** is defined as the decrease in oxidation state or the gain of electrons.

2. **Evaluate the statement**:
- The reason incorrectly states that a decrease in oxidation number or gaining of electrons means oxidation, which is contrary to the definitions.
- Therefore, the reason is also **false**.

### Final Conclusion
Both the assertion and the reason are false. Thus, the correct answer is option D: both assertion and reason are false.

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