The order of the oxidation state of the phos- phorus atom in `H_3PO_2, H_3PO_4 , H_3PO_3` and `H_4P_2O_6` is : -

Options

A. `H_3PO_4 gt H_3PO_2 gt H_3PO_3 gt H_4P_2O_6`
B. `H_3PO_4 gt H_2P_2O_6 gt H_3PO_3 gt H_3PO_2`
C. `H_3PO_2 gt H_3PO_3 gt H_4P_2O_6 gt H_3PO_4`
D. `H_3PO_4 gt H_3PO_2 gt H_3PO_4 gt H_4P_2O_6`

Answer

To determine the order of the oxidation state of the phosphorus atom in the compounds \( H_3PO_2 \), \( H_3PO_4 \), \( H_3PO_3 \), and \( H_4P_2O_6 \), we need to calculate the oxidation state of phosphorus in each compound step by step.

### Step 1: Calculate the oxidation state of phosphorus in \( H_3PO_2 \)

1. **Identify the oxidation states of other elements**:
- Hydrogen (H) has an oxidation state of +1.
- Oxygen (O) has an oxidation state of -2.

2. **Set up the equation**:
\[ 3(+1) + x + 2(-2) = 0 \]
where \( x \) is the oxidation state of phosphorus.

3. **Solve the equation**:
\[ 3 + x - 4 = 0 \implies x - 1 = 0 \implies x = +1 \]

### Step 2: Calculate the oxidation state of phosphorus in \( H_3PO_4 \)

1. **Set up the equation**:
\[ 3(+1) + x + 4(-2) = 0 \]

2. **Solve the equation**:
\[ 3 + x - 8 = 0 \implies x - 5 = 0 \implies x = +5 \]

### Step 3: Calculate the oxidation state of phosphorus in \( H_3PO_3 \)

1. **Set up the equation**:
\[ 3(+1) + x + 3(-2) = 0 \]

2. **Solve the equation**:
\[ 3 + x - 6 = 0 \implies x - 3 = 0 \implies x = +3 \]

### Step 4: Calculate the oxidation state of phosphorus in \( H_4P_2O_6 \)

1. **Set up the equation**:
\[ 4(+1) + 2x + 6(-2) = 0 \]

2. **Solve the equation**:
\[ 4 + 2x - 12 = 0 \implies 2x - 8 = 0 \implies 2x = 8 \implies x = +4 \]

### Summary of Oxidation States
- \( H_3PO_2 \): +1
- \( H_3PO_4 \): +5
- \( H_3PO_3 \): +3
- \( H_4P_2O_6 \): +4

### Step 5: Arrange in order of oxidation states
The order of the oxidation states of phosphorus in the compounds is:
1. \( H_3PO_4 \) (+5)
2. \( H_4P_2O_6 \) (+4)
3. \( H_3PO_3 \) (+3)
4. \( H_3PO_2 \) (+1)

### Final Answer
The order of the oxidation state of phosphorus in \( H_3PO_2, H_3PO_4, H_3PO_3, \) and \( H_4P_2O_6 \) is:
\[ H_3PO_4 > H_4P_2O_6 > H_3PO_3 > H_3PO_2 \]