Assertion : Treatment of chloroethane with a saturated solution of AgCN gives ethyl isocyanide as the major product.
Reason : Cyanide`(CN^-)` is an ambident nucelophile

Options

A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion
B. Both Assertion and Reason are true and Reason is not the correct explanation of Assertion
C. Assertion is true but Reason is false
D. Both Assertion and Reason are false

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 the treatment of chloroethane (C2H5Cl) with a saturated solution of AgCN results in the formation of ethyl isocyanide (C2H5NC) as the major product.
- Chloroethane can be represented as CH3CH2Cl.

2. **Identifying the Reaction**:
- The reaction involves a nucleophilic substitution where the nucleophile is CN⁻ (cyanide ion).
- In this context, AgCN is used, which provides the CN⁻ ion for the reaction.

3. **Understanding the Role of AgCN**:
- AgCN dissociates in solution to give Ag⁺ and CN⁻.
- The cyanide ion (CN⁻) is an ambident nucleophile, meaning it can attack from either the carbon or nitrogen atom.

4. **Analyzing the Nucleophilic Attack**:
- Due to the presence of silver (Ag), the bond between Ag and CN is covalent. This means that the carbon atom in CN⁻ is less nucleophilic, and the nitrogen atom becomes the more favorable site for nucleophilic attack.
- Therefore, the nitrogen atom of CN⁻ attacks the carbon atom of chloroethane, leading to the formation of ethyl isocyanide.

5. **Formation of Products**:
- The reaction can be summarized as follows:
- CH3CH2Cl + CN⁻ → CH3CH2NC (ethyl isocyanide) + Cl⁻
- The Cl⁻ ion will then bond with Ag⁺ to form AgCl.

6. **Conclusion on the Assertion**:
- The assertion is true because ethyl isocyanide is indeed formed as the major product.

7. **Understanding the Reason**:
- The reason states that cyanide (CN⁻) is an ambident nucleophile.
- While this is true, it does not directly explain why ethyl isocyanide is the major product in this specific reaction.

8. **Final Evaluation**:
- Both the assertion and reason are true statements, but the reason does not correctly explain the assertion.
- Therefore, the correct conclusion is that both the assertion and reason are true, but the reason is not the correct explanation for the assertion.

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