Which behaves both as a nucleophile as well as an electrophile?

Options

A. `CH_3OH`
B. `CH_3NH_2`
C. `CH_3CN`
D. `CH_3Cl`

Answer

To determine which compound behaves both as a nucleophile and an electrophile, we need to analyze the characteristics of potential candidates based on their electronic structure.

### Step-by-Step Solution:

1. **Understanding Nucleophiles and Electrophiles**:
- Nucleophiles are species that are rich in electrons and can donate an electron pair to an electron-deficient site (electrophile).
- Electrophiles are electron-deficient species that can accept an electron pair from a nucleophile.

2. **Analyzing CH3OH (Methanol)**:
- Methanol has 6 valence electrons and 2 lone pairs on the oxygen atom, making it a potential nucleophile.
- However, it does not have a suitable site to accept electrons (no electron-deficient carbon), so it cannot act as an electrophile.
- Conclusion: CH3OH can act as a nucleophile but not as an electrophile.

3. **Analyzing CH3CN (Methyl Cyanide)**:
- Methyl cyanide (CH3CN) can be represented as CH3C≡N. The carbon in the cyanide group is bonded to a highly electronegative nitrogen atom.
- The nitrogen atom has a lone pair of electrons, allowing CH3CN to act as a nucleophile.
- The carbon atom in the cyanide group has a partial positive charge due to the electronegativity of nitrogen, making it electron-deficient and capable of acting as an electrophile.
- Conclusion: CH3CN can act as both a nucleophile (due to the nitrogen) and an electrophile (due to the carbon).

4. **Analyzing Other Candidates**:
- Other candidates like CH3Cl (Chloromethane) were also considered, but they can only act as nucleophiles and not as electrophiles due to the saturation and lack of electron-deficient sites.
- Conclusion: CH3Cl cannot act as both a nucleophile and an electrophile.

5. **Final Conclusion**:
- The only compound that behaves both as a nucleophile and an electrophile is CH3CN (Methyl Cyanide).

### Final Answer:
**CH3CN behaves both as a nucleophile and an electrophile.**

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