Which of the compound on reaction with ` Li AIH_4 ` gives ethyl amine ?

Options

A. Acetamide
B. Acetonitrile
C. Cyanomethane
D. All of these

Answer

To determine which compound reacts with lithium aluminum hydride (LiAlH4) to produce ethylamine (C2H5NH2), we can analyze each option provided. Ethylamine has the structure CH3CH2NH2.

### Step-by-Step Solution:

1. **Identify the Structure of Ethylamine**:
- Ethylamine is represented as CH3CH2NH2.

2. **Analyze the First Compound: Acetamide (CH3C(=O)NH2)**:
- Acetamide is a carbonyl compound (C=O) attached to an amine (NH2).
- When acetamide reacts with LiAlH4, the hydride ion (H-) attacks the carbonyl carbon, leading to the formation of an iminium ion.
- The iminium ion is then further reduced by another hydride ion from LiAlH4, resulting in ethylamine (CH3CH2NH2).

3. **Analyze the Second Compound: Acetonitrile (CH3C≡N)**:
- Acetonitrile contains a triple bond between carbon and nitrogen.
- Upon reaction with LiAlH4, the hydride ion attacks the carbon of the nitrile, forming an imine intermediate.
- This intermediate can then be further reduced to yield ethylamine (CH3CH2NH2).

4. **Analyze the Third Compound: Cyanomethane (CH3C≡N)**:
- Cyanomethane is structurally similar to acetonitrile.
- The reaction mechanism is the same as that for acetonitrile, where the hydride ion attacks the carbon of the nitrile, leading to the formation of ethylamine (CH3CH2NH2).

5. **Conclusion**:
- All three compounds (acetamide, acetonitrile, and cyanomethane) can react with LiAlH4 to produce ethylamine.
- Therefore, the correct answer is **D) All of these**.