In the reaction `P_(4)+3OH^(-)+3H_(2)Oto3H_(2)PO_(2)^(-)+PH_(3)` phosphorus is undergoing.

Options

A. oxidation
B. reduction
C. disproportionation
D. hydrolysis

Answer

To determine the oxidation states of phosphorus in the given reaction and identify the type of reaction, we can follow these steps:

### Step 1: Write the balanced chemical equation
The reaction is given as:
\[ P_4 + 3OH^- + 3H_2O \rightarrow 3H_2PO_2^- + PH_3 \]

### Step 2: Determine the oxidation state of phosphorus in \( P_4 \)
In the elemental form \( P_4 \), the oxidation state of phosphorus is:
- **Oxidation state of phosphorus in \( P_4 \)** = 0 (since it is in its elemental state).

### Step 3: Determine the oxidation state of phosphorus in \( H_2PO_2^- \)
Let the oxidation state of phosphorus in \( H_2PO_2^- \) be \( x \). The equation for the oxidation state can be set up as follows:
\[ 2(+1) + x + 2(-2) = -1 \]
This simplifies to:
\[ 2 + x - 4 = -1 \implies x - 2 = -1 \implies x = +1 \]
- **Oxidation state of phosphorus in \( H_2PO_2^- \)** = +1.

### Step 4: Determine the oxidation state of phosphorus in \( PH_3 \)
Let the oxidation state of phosphorus in \( PH_3 \) be \( y \). The equation for the oxidation state can be set up as follows:
\[ y + 3(+1) = 0 \]
This simplifies to:
\[ y + 3 = 0 \implies y = -3 \]
- **Oxidation state of phosphorus in \( PH_3 \)** = -3.

### Step 5: Analyze the changes in oxidation states
Now we compare the oxidation states:
- In \( P_4 \): 0
- In \( H_2PO_2^- \): +1
- In \( PH_3 \): -3

### Step 6: Identify the type of reaction
In this reaction:
- Phosphorus goes from an oxidation state of 0 to +1 (oxidation).
- Phosphorus also goes from an oxidation state of 0 to -3 (reduction).

Since the same element (phosphorus) is undergoing both oxidation and reduction, this reaction is classified as a **disproportionation reaction**.

### Conclusion
Thus, the final answer is that phosphorus is undergoing a disproportionation reaction.

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