A : The valency and oxidation number of sulphur in `S_(8)` respectively are 2 and 0 .
R : `S_(8)` Rhombic is the most stable allotropic form of sulphur .

Options

A. If both Assertion & Reason are true and the reason is the correct explanation of the assertion , then mark (1)
B. If both Assertion & Reason are true but the reason is not the correct explanation of the assertion , then mark (2)
C. If Assertion is true statement but Reason is false , then mark (3)
D. If both Assertion and Reason are false statements , then mark (4)

Answer

To solve the given assertion and reason question, we will analyze both statements step by step.

### Step 1: Analyze the Assertion
**Assertion**: The valency and oxidation number of sulfur in \( S_8 \) respectively are 2 and 0.

- **Valency of Sulfur**: In the \( S_8 \) molecule, sulfur atoms are arranged in a cyclic structure where each sulfur atom forms two covalent bonds with its neighboring sulfur atoms. Therefore, the valency of sulfur in \( S_8 \) is indeed 2.

- **Oxidation Number of Sulfur**: In a neutral molecule like \( S_8 \), the overall charge is zero. The oxidation number of sulfur can be calculated as follows:
\[ 8 \times x = 0 \implies x = 0 \]
Thus, the oxidation number of sulfur in \( S_8 \) is 0.

**Conclusion for Assertion**: Both parts of the assertion are true: the valency of sulfur is 2 and the oxidation number is 0.

### Step 2: Analyze the Reason
**Reason**: \( S_8 \) Rhombic is the most stable allotropic form of sulfur.

- **Stability of \( S_8 \)**: The rhombic form of sulfur (also known as alpha-sulfur) is indeed the most stable allotrope at room temperature. Other allotropes, such as \( S_{12} \) and \( S_{18} \), are less stable and typically require higher temperatures to exist.

**Conclusion for Reason**: The reason is also true, as \( S_8 \) in its rhombic form is the most stable allotrope of sulfur at room temperature.

### Step 3: Relationship Between Assertion and Reason
While both the assertion and reason are true, the reason does not explain the assertion. The assertion discusses the valency and oxidation state of sulfur, while the reason discusses the stability of the \( S_8 \) allotrope. Therefore, the reason does not provide a justification for the assertion.

### Final Conclusion
- **Assertion**: True
- **Reason**: True
- **Explanation**: The reason does not explain the assertion.

### Answer:
Both the assertion and reason are true, but the reason is not a correct explanation of the assertion.

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