`MnO_(2)+4H^(+)+e^(-)rarrMn^(+3)+2H_(2)O`
In the above reaction oxidation number of Mn change from :-

Options

A. `+2` to `-3`
B. `+4` to `-3`
C. `+2` to `+3`
D. `+4` to `+3`

Answer

To determine the change in the oxidation number of manganese (Mn) in the reaction provided, we can follow these steps:

### Step 1: Identify the oxidation states of Mn in the reactants and products.
- In the reactant MnO₂, we need to find the oxidation state of Mn.
- The oxidation state of oxygen (O) is typically -2.

### Step 2: Set up the equation for MnO₂.
- Let the oxidation state of Mn be \( x \).
- The formula for MnO₂ can be expressed as:
\[ x + 2(-2) = 0 \]
- This simplifies to:
\[ x - 4 = 0 \]
- Therefore, \( x = +4 \).

### Step 3: Determine the oxidation state of Mn in the product.
- In the product Mn³⁺, the oxidation state of Mn is +3.

### Step 4: Calculate the change in oxidation state.
- The oxidation state of Mn changes from +4 in MnO₂ to +3 in Mn³⁺.
- This indicates a decrease in oxidation state, which means Mn is being reduced.

### Step 5: Summarize the change.
- The oxidation number of Mn changes from +4 to +3.

### Conclusion:
- Therefore, the oxidation number of Mn changes from +4 to +3 in the reaction.

### Answer:
The oxidation number of Mn changes from +4 to +3.

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