Cyanide ion acts as an ambident nucleophille. From which end it acts as a strong nucleophile in aqueous medium? Give reason for your answer.

Options

A. It act as a stronger nucleophile from carbon end.
B. It acts as a stronger nucleophile from nitrogen end.
C. It depends on the nature of the alkyl halide.
D. It has same strength from both the ends.

Explanation

To determine from which end the cyanide ion (CN⁻) acts as a stronger nucleophile in an aqueous medium, we need to analyze the structure and properties of the cyanide ion.

### Step-by-Step Solution:

1. **Understanding the Cyanide Ion**: The cyanide ion consists of a carbon atom triple-bonded to a nitrogen atom (C≡N). This gives it two potential nucleophilic sites: the carbon atom (C) and the nitrogen atom (N).

2. **Nucleophilicity**: A nucleophile is a species that donates an electron pair to form a chemical bond. The strength of a nucleophile is influenced by its ability to donate electrons.

3. **Comparison of Nucleophilic Sites**:
- **Carbon End**: When the cyanide ion acts as a nucleophile from the carbon end, it forms a carbon-carbon (C-C) bond with the electrophile. This bond is typically stronger due to the similarity of the atoms involved (both being carbon).
- **Nitrogen End**: If the cyanide ion acts from the nitrogen end, it forms a carbon-nitrogen (C-N) bond. While this bond is also stable, it is generally weaker than a C-C bond due to the difference in electronegativity between carbon and nitrogen.

4. **Effect of Aqueous Medium**: In an aqueous medium, the solvent can stabilize charged species. However, the intrinsic nucleophilicity of the cyanide ion remains more pronounced from the carbon end because the C-C bond formation is more favorable.

5. **Conclusion**: Therefore, the cyanide ion acts as a stronger nucleophile from the carbon end in aqueous medium. This is because the formation of a C-C bond is more stable and energetically favorable compared to the formation of a C-N bond.

### Final Answer:
The cyanide ion acts as a stronger nucleophile from the carbon end in aqueous medium due to the formation of a stronger and more stable carbon-carbon bond compared to a carbon-nitrogen bond.

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