A : Diphenyl ether is prepared by Williamson synthesis .
R : This reaction generally proceed by `S_(N)1` mechanism .

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 assertion and reason question regarding diphenyl ether and its preparation via Williamson synthesis, we can break down the solution into clear steps.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that diphenyl ether is prepared by Williamson synthesis.
- Williamson synthesis involves the reaction of an alkoxide ion with an alkyl halide to form an ether.

2. **Identifying Diphenyl Ether**:
- Diphenyl ether (C12H10O) consists of two phenyl groups (C6H5) connected by an oxygen atom.
- To synthesize diphenyl ether using Williamson synthesis, one would typically use a phenoxide ion as the nucleophile and an aryl halide as the electrophile.

3. **Mechanism of Williamson Synthesis**:
- In Williamson synthesis, the nucleophile attacks the electrophile, resulting in the substitution of the leaving group (halide) by the alkoxide ion.
- However, in the case of aryl halides, the leaving group is not easily displaced due to resonance stabilization of the aryl halide.

4. **Evaluating the Reason**:
- The reason states that this reaction generally proceeds by an SN1 mechanism.
- In an SN1 mechanism, the first step involves the formation of a carbocation after the leaving group departs.

5. **Analyzing the Feasibility of SN1 for Diphenyl Ether Formation**:
- For diphenyl ether synthesis via SN1, one would need to form a phenyl cation, which is highly unstable due to the lack of sufficient stabilization.
- Therefore, the formation of a phenyl cation is not feasible, making the SN1 mechanism unsuitable for this reaction.

6. **Conclusion**:
- Since diphenyl ether cannot be synthesized effectively through Williamson synthesis due to the instability of the phenyl cation and the inability of aryl halides to undergo SN1 reactions, both the assertion and the reason are incorrect.

### Final Answer:
Both the assertion (A) and the reason (R) are incorrect.