The oxidation number of phosphorus in `PH_(4)^(+),PO_(2)^(3-),PO_(4)^(3-) and PO_(3)^(3-)` are respectively :-

Options

A. `-3,+1,+3,+5`
B. `-3,+3,+5,+1`
C. `+3,-3,+5,+1`
D. `-3,+1,+5,+3`

Answer

To find the oxidation number of phosphorus in the compounds \( PH_4^+, PO_2^{3-}, PO_4^{3-}, \) and \( PO_3^{3-} \), we can follow these steps:

### Step 1: Determine the oxidation state in \( PH_4^+ \)

1. **Set up the equation**: Let the oxidation state of phosphorus be \( x \).
2. **Identify the oxidation states of hydrogen**: Hydrogen has an oxidation state of +1.
3. **Write the equation**:
\[ x + 4(+1) = +1 \]
4. **Solve for \( x \)**:
\[ x + 4 = +1 \\ x = +1 - 4 \\ x = -3 \]
5. **Conclusion**: The oxidation state of phosphorus in \( PH_4^+ \) is **-3**.

### Step 2: Determine the oxidation state in \( PO_2^{3-} \)

1. **Set up the equation**: Let the oxidation state of phosphorus be \( x \).
2. **Identify the oxidation states of oxygen**: Oxygen has an oxidation state of -2.
3. **Write the equation**:
\[ x + 2(-2) = -3 \]
4. **Solve for \( x \)**:
\[ x - 4 = -3 \\ x = -3 + 4 \\ x = +1 \]
5. **Conclusion**: The oxidation state of phosphorus in \( PO_2^{3-} \) is **+1**.

### Step 3: Determine the oxidation state in \( PO_4^{3-} \)

1. **Set up the equation**: Let the oxidation state of phosphorus be \( x \).
2. **Write the equation**:
\[ x + 4(-2) = -3 \]
3. **Solve for \( x \)**:
\[ x - 8 = -3 \\ x = -3 + 8 \\ x = +5 \]
4. **Conclusion**: The oxidation state of phosphorus in \( PO_4^{3-} \) is **+5**.

### Step 4: Determine the oxidation state in \( PO_3^{3-} \)

1. **Set up the equation**: Let the oxidation state of phosphorus be \( x \).
2. **Write the equation**:
\[ x + 3(-2) = -3 \]
3. **Solve for \( x \)**:
\[ x - 6 = -3 \\ x = -3 + 6 \\ x = +3 \]
4. **Conclusion**: The oxidation state of phosphorus in \( PO_3^{3-} \) is **+3**.

### Final Summary of Oxidation States

- \( PH_4^+ \): -3
- \( PO_2^{3-} \): +1
- \( PO_4^{3-} \): +5
- \( PO_3^{3-} \): +3

Thus, the oxidation numbers of phosphorus in the respective compounds are **-3, +1, +5, +3**.