Balance the chemical equation by the oxidation number method.
(iii) `FeS_(2) + O_(2) to Fe_(2)O_(3) + SO_(2)`

Explanation

To balance the chemical equation `FeS₂ + O₂ → Fe₂O₃ + SO₂` using the oxidation number method, follow these steps:

### Step 1: Assign Oxidation Numbers
- **Iron (Fe)** in `FeS₂`: Each Fe is in the +2 oxidation state.
- **Sulfur (S)** in `FeS₂`: Each S is in the -1 oxidation state.
- **Oxygen (O)** in `O₂`: O is in the 0 oxidation state (elemental form).
- **Iron (Fe)** in `Fe₂O₃`: Each Fe is in the +3 oxidation state.
- **Sulfur (S)** in `SO₂`: Each S is in the +4 oxidation state.
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