Assertion( A) KCN reacts with methyl chloride to give methyl isocyanide.
Reason (R) `CN^(-)` is an ambident nucleophile.

Options

A. Assertion and reason both are correct and reason is correct explanation of assertion
B. Assertion and reason both are wrong statements
C. Assertion is correct but reason is wrong statement
D. Assertion is wrong but reason is correct statement.

Explanation

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 KCN reacts with methyl chloride (CH3Cl) to give methyl isocyanide (CH3NC).
- Methyl chloride is a primary alkyl halide, and KCN is potassium cyanide, which dissociates to give CN⁻ ions.

2. **Reaction Mechanism:**
- CN⁻ is an ambident nucleophile, meaning it can attack from two different sites: the carbon atom (C) or the nitrogen atom (N).
- When CN⁻ attacks methyl chloride, it can either form methyl cyanide (CH3C≡N) if the carbon atom is the attacking site or methyl isocyanide (CH3N≡C) if the nitrogen atom is the attacking site.

3. **Analyzing the Reaction with KCN:**
- In the case of KCN reacting with methyl chloride, the carbon atom of CN⁻ is more likely to attack the carbon of methyl chloride due to the stability of the resulting carbon-carbon bond.
- Therefore, the reaction primarily yields methyl cyanide (CH3C≡N), not methyl isocyanide.

4. **Understanding the Reason:**
- The reason states that CN⁻ is an ambident nucleophile, which is indeed correct. It can attack either through the carbon or nitrogen atom due to the delocalization of the negative charge.

5. **Conclusion:**
- The assertion is incorrect because KCN does not produce methyl isocyanide when reacting with methyl chloride; it produces methyl cyanide instead.
- The reason is correct since CN⁻ is an ambident nucleophile.

### Final Answer:
- The correct option is: **Assertion is wrong but reason is correct.** (Option 4)