Assertion: In vapour state sulphur is paramagnetic in nature.
Reason : In vapour state sulphur exists as `S_(2)` molecule.

Options

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

Answer

To solve the question, we need to evaluate both the assertion and the reason provided.

### Step 1: Analyze the Assertion
The assertion states that "In vapor state, sulfur is paramagnetic in nature."

- **Paramagnetism** is a property of materials that have unpaired electrons. These unpaired electrons create a magnetic moment, causing the material to be attracted to a magnetic field.

### Step 2: Analyze the Reason
The reason states that "In vapor state, sulfur exists as S2 molecule."

- In its solid state, sulfur typically exists as an S8 molecule (a crown-shaped structure). However, when sulfur is heated to a high temperature, it can dissociate into smaller molecules, including S2.

### Step 3: Determine the Electronic Configuration of S2
To understand the paramagnetic nature of S2, we need to look at its electronic configuration using Molecular Orbital Theory.

1. The molecular orbital configuration for S2 can be represented as:
- σ(1s)² σ*(1s)² σ(2s)² σ*(2s)² σ(2p_z)² π(2p_x)² π(2p_y)² π*(2p_x)¹ π*(2p_y)¹

2. From this configuration, we can observe that S2 has two unpaired electrons in the π*(2p_x) and π*(2p_y) orbitals.

### Step 4: Conclusion
Since S2 has unpaired electrons, it is indeed paramagnetic in the vapor state. Therefore, both the assertion and the reason are correct, and the reason correctly explains the assertion.

### Final Answer
Both the assertion and reason are true, and the reason is the correct explanation of the assertion.