Isocyanide is formed as the major product of the reaction when alkyl halide is treated with one the following

Options

A. `AgNO_2`
B. `KNO_2`
C. `AgCN`
D. `KCN`

Explanation

To determine the major product when an alkyl halide is treated with a specific reagent that leads to the formation of isocyanide, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Alkyl Halide**: Start with an alkyl halide (R-X), where R is the alkyl group and X is the halogen (like Cl, Br, or I).

2. **Choose the Reagent**: The reagent that leads to the formation of isocyanide is typically silver cyanide (AgCN). This reagent is crucial because it has a different mechanism of action compared to other cyanide sources.

3. **Understand the Reaction Mechanism**:
- When the alkyl halide (R-X) reacts with silver cyanide (AgCN), the halogen (X) is replaced by the isocyanide group (N≡C).
- The reaction can be represented as:
\[ R-X + AgCN \rightarrow R-NC + AgX \]
- Here, AgX is a byproduct, and R-NC is the isocyanide formed.

4. **Nucleophilic Attack**: In this reaction, the nitrogen in AgCN acts as a nucleophile. It attacks the electrophilic carbon of the alkyl halide, leading to the formation of the isocyanide (R-NC).

5. **Final Product**: The major product of the reaction is thus isocyanide (R-NC), while AgX is formed as a secondary product.

### Conclusion:
When an alkyl halide is treated with silver cyanide (AgCN), the major product formed is isocyanide (R-NC).

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