One litre of an acidified solution of `KMnO_4` containing 15 g of `KMnO_4` is decolourised by passing sufficient amount of `SO_2`. If `SO_2`. If `SO_2` is produced by roasting of iron pyrites `(FeS_2)`. What will be the amount of pyrites required to produce the necessary amount of `SO_2`

Explanation

To solve the problem, we need to determine how much iron pyrites (FeS₂) is required to produce a sufficient amount of sulfur dioxide (SO₂) to decolorize the given amount of potassium permanganate (KMnO₄).

### Step-by-Step Solution:

1. **Calculate the Molar Mass of KMnO₄:**
- The molar mass of KMnO₄ is calculated as follows:
- K: 39 g/mol
- Mn: 55 g/mol
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