A : Phenol is manufactured by Dow 's pocess.
R : It involves the formation of benzyne intermediate .

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 question regarding the assertion and reason related to the manufacturing of phenol by Dow's process, we can break down the solution into clear steps:

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that "Phenol is manufactured by Dow's process."
- This is a true statement. Dow's process is a well-known method for synthesizing phenol from chlorobenzene.

**Hint**: Recall the main methods of phenol production and identify which one involves chlorobenzene.

2. **Understanding the Reason (R)**:
- The reason states that "It involves the formation of benzyne intermediate."
- This is also a true statement. In Dow's process, the reaction of chlorobenzene with sodium hydroxide (NaOH) under specific conditions leads to the formation of a benzyne intermediate.

**Hint**: Consider the reaction mechanism and the role of intermediates in organic synthesis.

3. **Analyzing the Dow’s Process**:
- In Dow's process, chlorobenzene reacts with NaOH at high temperature and pressure (623 K and 300 atm).
- The reaction produces sodium phenoxide as an intermediate, which can be converted to phenol by acidification.

**Hint**: Think about the reaction conditions and the products formed during the process.

4. **Conclusion**:
- Both the assertion and reason are true, and the reason correctly explains the assertion.
- Therefore, the correct answer is that both statements are true, and the reason is the correct explanation for the assertion.

**Hint**: Confirm that the relationship between the assertion and reason is logical and that the reason supports the assertion.

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