`H_(3)PO_(2)andH_(3)PO_(3)` act as good reducing agents but `H_(3)PO_(4)` does not. Explain.

Explanation

To explain why \( H_3PO_2 \) (phosphorous acid) and \( H_3PO_3 \) (phosphoric acid) act as good reducing agents while \( H_3PO_4 \) (phosphoric acid) does not, we can analyze the oxidation states of phosphorus in each compound and their ability to change these states.

### Step-by-Step Solution:

1. **Identify the Oxidation States**:
- For \( H_3PO_2 \):
- Let the oxidation state of phosphorus (P) be \( x \).
- The equation for the oxidation state is:
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