Balance the following equations in basic medium by ion electron method and oxidation number method and identify the oxidising agent and the reducing agent.
`P_(4)(s)+OH^(-)(aq)toPH_(3)(g)+H_(2)PO_(2)^(-)(aq)`

Explanation

To balance the equation \( P_4(s) + OH^-(aq) \rightarrow PH_3(g) + H_2PO_2^-(aq) \) in basic medium using both the ion-electron method and the oxidation number method, we will follow these steps:

### Step 1: Assign Oxidation Numbers
1. **Identify oxidation states**:
- In \( P_4 \), phosphorus (P) has an oxidation state of 0.
- In \( PH_3 \), let the oxidation state of P be \( x \). The equation becomes \( x + 3(+1) = 0 \), thus \( x = -3 \).
- In \( H_2PO_2^- \), let the oxidation state of P be \( x \). The equation becomes \( x + 2(+1) + 2(-2) = -1 \), thus \( x + 2 - 4 = -1 \) leading to \( x = +1 \).

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