(ii) Find the oxidation number of:
(1) S in `Na_(2)S_(4)O_(6)`
(2) Cr in `K_(2)CrO_(7)`
(3) Mn in `K_(2)MnO_(4)`
(4) Fe in `Fe_(3)O_(4)`

Explanation

To find the oxidation numbers of the specified elements in the given compounds, we can follow these steps:

### 1. Finding the oxidation number of S in Na₂S₄O₆

**Step 1:** Write the oxidation states of known elements in the compound.
- Sodium (Na) has an oxidation state of +1.
- Oxygen (O) has an oxidation state of -2.

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