Which of the following can be employed for the conversion of potassium manganate to potassium permanganate?

Options

A. `O_3`
B. `Cl_2`
C. Electrolysis
D. All

Answer

To solve the question regarding the conversion of potassium manganate (K2MnO4) to potassium permanganate (KMnO4), we can analyze the methods provided in the options.

### Step-by-Step Solution:

1. **Understanding the Compounds**:
- Potassium manganate (K2MnO4) is a green compound, while potassium permanganate (KMnO4) is a purple compound. The conversion involves oxidation of manganese from a +6 oxidation state in manganate to a +7 oxidation state in permanganate.

2. **Identifying the Methods of Conversion**:
- The question asks which methods can be used for this conversion. We will evaluate each option provided.

3. **Option Analysis**:
- **Option 1: Ozone (O3)**:
- When ozone is passed through an aqueous solution of potassium manganate, it oxidizes K2MnO4 to KMnO4.
- Reaction:
\[ 2 \text{KMnO}_4 + \text{KOH} + \text{O}_2 \rightarrow 2 \text{KMnO}_4 \]
- This method is valid for the conversion.

- **Option 2: Chlorine (Cl2)**:
- Chlorine can also oxidize potassium manganate to potassium permanganate.
- Reaction:
\[ 2 \text{K}_2\text{MnO}_4 + \text{Cl}_2 \rightarrow 2 \text{KMnO}_4 + 2 \text{KCl} \]
- This method is also valid for the conversion.

- **Option 3: Electrolysis**:
- Electrolytic oxidation in an alkaline medium can convert K2MnO4 to KMnO4.
- This method is valid as well.

4. **Conclusion**:
- All the methods listed (ozone, chlorine, and electrolysis) can be employed for the conversion of potassium manganate to potassium permanganate.
- Therefore, the correct answer is that all the options provided can be used for this conversion.

### Final Answer:
All of the above methods (ozone, chlorine, and electrolysis) can be employed for the conversion of potassium manganate to potassium permanganate.