Assertion : In `SO_(3)` molecule bond dissociation energy of all S=O bonds are not equivalent.
Reason : `SO_(3)` molecule is having two types of `2 p pi - 3 p pi and 2p pi- 3d pi` pi-bonds.

Options

A. If assertion is true but the reason is false
B. If assertion is false but reason is true
C. IF both assertion and reason are true and the reason is the correct explanation of assertion
D. If both assertion and reason are true but reason is not the correct explanation of assertion

Answer

To analyze the assertion and reason provided in the question regarding the molecule SO₃ (sulfur trioxide), we will break down the information step by step.

### Step 1: Understand the Assertion
The assertion states that in the SO₃ molecule, the bond dissociation energy of all S=O bonds are not equivalent.

**Analysis**:
- In SO₃, sulfur is bonded to three oxygen atoms through double bonds (S=O).
- The bond dissociation energy refers to the energy required to break a bond. If all S=O bonds were equivalent, they would have the same bond dissociation energy.

### Step 2: Understand the Reason
The reason states that SO₃ has two types of bonds: 2pπ-3pπ and 2pπ-3dπ π-bonds.

**Analysis**:
- In SO₃, the sulfur atom can utilize its 3p and 3d orbitals for bonding with oxygen.
- The presence of different types of overlapping (2pπ with 3pπ and 2pπ with 3dπ) suggests that the bonds may not be equivalent due to the different orbital interactions.

### Step 3: Analyze the Structure of SO₃
- Sulfur has 6 valence electrons and forms three double bonds with oxygen.
- The hybridization of sulfur in SO₃ is sp², leading to a trigonal planar geometry.
- In a trigonal planar structure, the bond lengths and angles are generally equivalent due to the symmetrical arrangement of the bonds.

### Step 4: Conclusion on Assertion and Reason
- The assertion is **false** because, despite the different types of bonds, the hybridization leads to equivalent bond lengths and energies in the SO₃ molecule.
- The reason is **true** in that SO₃ does involve different types of π-bonding interactions, but this does not affect the equivalence of bond energies due to hybridization.

### Final Answer
- The assertion is false, while the reason is true. Therefore, the correct option is that the assertion is false, but the reason is true.

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