Assertion (A) : `C Cl_4` is inert towards hydrolysis but `SiCl_4` is readily hyrolyse .
Reason (R) : Carbon cannot expand its octet but silicon can expand its octet .

Options

A. If both (A) and (R) are correct and (R) is correct explanation of (A)
B. If both (A) and (R) are correct and (R) is not correct explanation of (A)
C. If (A) is correct , but (R) is incorrect
D. If (A) is incorrect but (R) is correct .

Answer

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

### Step-by-Step Solution:

1. **Understanding the Assertion:**
- The assertion states that \( \text{CCl}_4 \) (carbon tetrachloride) is inert towards hydrolysis, while \( \text{SiCl}_4 \) (silicon tetrachloride) readily undergoes hydrolysis.
- Hydrolysis refers to the reaction of a compound with water, which can lead to the formation of new products.

2. **Analyzing \( \text{CCl}_4 \):**
- Carbon in \( \text{CCl}_4 \) has an electronic configuration of \( 1s^2, 2s^2, 2p^2 \).
- Carbon does not have available d-orbitals to accommodate additional electrons, meaning it cannot expand its octet.
- Therefore, \( \text{CCl}_4 \) does not react with water, making it inert towards hydrolysis.

3. **Analyzing \( \text{SiCl}_4 \):**
- Silicon, on the other hand, has an electronic configuration of \( 1s^2, 2s^2, 2p^6, 3s^2, 3p^2 \).
- Silicon has vacant 3d orbitals that can participate in bonding, allowing it to expand its octet.
- This ability to accommodate additional electrons enables \( \text{SiCl}_4 \) to react with water, leading to hydrolysis.

4. **Conclusion on the Assertion:**
- Since \( \text{CCl}_4 \) is indeed inert towards hydrolysis and \( \text{SiCl}_4 \) readily hydrolyzes, the assertion is correct.

5. **Understanding the Reason:**
- The reason states that carbon cannot expand its octet, but silicon can.
- This statement is true because carbon lacks d-orbitals, while silicon has empty d-orbitals that allow it to expand its octet during chemical reactions.

6. **Conclusion on the Reason:**
- The reason correctly explains why \( \text{CCl}_4 \) is inert and \( \text{SiCl}_4 \) is reactive towards hydrolysis.

### Final Answer:
Both the assertion and the reason are correct, and the reason provides a correct explanation for the assertion. Therefore, the answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

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