The correct order of acidic strength of the following is

Options

A. `P_2O_5 gt SO_3 gt Cl_2 O_7 gt SO_2 `
B. `Cl_2 O_7 gt SO_3 gt P_2 O_5 gt SO_2 `
C. `SO_3 gt Cl_2 O_7 gt P_2 O_5 gt SO_2 `
D. `P_2 O_5 gt SO_2 gt SO_3 gt Cl_2 O_7 `

Answer

To determine the correct order of acidic strength for the compounds P2O5, SO3, Cl2O7, and SO2, we need to analyze their oxidation states and how they relate to acidic strength.

### Step-by-Step Solution:

1. **Identify the Compounds**: We have four compounds to analyze: P2O5, SO3, Cl2O7, and SO2.

2. **Calculate Oxidation States**:
- **For P2O5**:
- Let the oxidation state of phosphorus (P) be \( x \).
- The formula is \( 2x + 5(-2) = 0 \) (since oxygen has an oxidation state of -2).
- Solving gives \( 2x - 10 = 0 \) → \( 2x = 10 \) → \( x = +5 \).
- Therefore, the oxidation state of phosphorus in P2O5 is +5.

- **For SO3**:
- Let the oxidation state of sulfur (S) be \( x \).
- The formula is \( x + 3(-2) = 0 \).
- Solving gives \( x - 6 = 0 \) → \( x = +6 \).
- Therefore, the oxidation state of sulfur in SO3 is +6.

- **For Cl2O7**:
- Let the oxidation state of chlorine (Cl) be \( x \).
- The formula is \( 2x + 7(-2) = 0 \).
- Solving gives \( 2x - 14 = 0 \) → \( 2x = 14 \) → \( x = +7 \).
- Therefore, the oxidation state of chlorine in Cl2O7 is +7.

- **For SO2**:
- Let the oxidation state of sulfur (S) be \( x \).
- The formula is \( x + 2(-2) = 0 \).
- Solving gives \( x - 4 = 0 \) → \( x = +4 \).
- Therefore, the oxidation state of sulfur in SO2 is +4.

3. **Compare Oxidation States**:
- P2O5: +5
- SO3: +6
- Cl2O7: +7
- SO2: +4

4. **Determine Acidic Strength**:
- Acidic strength generally increases with the oxidation state of the central atom in the oxides.
- Therefore, the order of acidic strength based on oxidation states is:
- Cl2O7 (+7) > SO3 (+6) > P2O5 (+5) > SO2 (+4)

5. **Final Order**:
- The correct order of acidic strength is: Cl2O7 > SO3 > P2O5 > SO2.

### Conclusion:
The correct order of acidic strength of the compounds is Cl2O7 > SO3 > P2O5 > SO2.