Pyrolusite is `MnO_(2)` used to prepare `KMnO_(4)`. Steps are, `MnO_(2)overset(I)(rarr)MnO_(4)^(2-)overset(II)(rarr)MnO_(4)^(-)` Steps I and II are respectively`:`

Options

A. Fuse with KOH//air, electrolytic reduction
B. Fuse with KOH/air, electrolytic oxidation
C. Fuse with con. `HNO_(3) //air`, electrolytic reduction
D. All are correct

Answer

To solve the question regarding the preparation of KMnO4 from pyrolusite (MnO2), we need to identify the two steps involved in the process. Here’s the step-by-step solution:

### Step 1: Reaction of MnO2 with Potassium Hydroxide and Air
1. **Identify the Reactants**: The first step involves the reaction of manganese dioxide (MnO2) with potassium hydroxide (KOH) in the presence of air (or an oxidizing agent).
2. **Reaction Process**: When MnO2 is fused with KOH and air, it gets oxidized, resulting in the formation of potassium manganate (K2MnO4).
3. **Balanced Equation**: The balanced chemical equation for this reaction is:
\[ 2 \text{MnO}_2 + 4 \text{KOH} + \text{O}_2 \rightarrow 2 \text{K}_2\text{MnO}_4 + 2 \text{H}_2\text{O} \]
Here, K2MnO4 is the dark green potassium manganate formed in this step.

### Step 2: Electrolytic Oxidation of MnO4^2-
1. **Identify the Intermediate Product**: The product from Step 1, K2MnO4, contains the manganate ion (MnO4^2-).
2. **Electrolytic Oxidation**: In the second step, the manganate ion (MnO4^2-) undergoes electrolytic oxidation.
3. **Formation of Permanganate**: This process converts the manganate ion into the permanganate ion (MnO4^-).
4. **Balanced Equation**: The reaction can be represented as:
\[ 2 \text{MnO}_4^{2-} \rightarrow 2 \text{MnO}_4^{-} + 2 \text{e}^- \]
This indicates that the manganate ion is oxidized to permanganate ion.

### Final Answer
- **Step I**: Fusion of MnO2 with KOH and air to form MnO4^2- (K2MnO4).
- **Step II**: Electrolytic oxidation of MnO4^2- to form MnO4^-.