Describe the preparation of potassium permanganate. How does the acidified permanganate solution react with oxalic acid? Write the ionic equation for the reaction.
OR
Describe the oxidising action of potassium dischromate and write the ionic equations for its reaction with (i) an iodide (ii) `H_(2)S`.

Explanation

### Step-by-Step Solution

**Preparation of Potassium Permanganate (KMnO4)**

1. **Starting Material**: The preparation begins with manganese dioxide (MnO2), commonly known as pyrolusite.

2. **Reaction with Potassium Hydroxide**: MnO2 is reacted with potassium hydroxide (KOH) in the presence of oxygen (O2) and heat. The reaction can be represented as:
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