Which one of the following reagent will convert acetamide to ethanamine?

Options

A. Phophorous pentoxide
B. Lithium aluminium hydride
C. Potassium cyanide
D. Thionyl chloride

Answer

To convert acetamide (CH3CO NH2) to ethanamine (CH3CH2NH2), we can use lithium aluminium hydride (LiAlH4) as the reagent. Here’s a step-by-step breakdown of the process:

### Step 1: Identify the Reactants
We start with acetamide, which has the structure CH3CO NH2. This compound consists of a carbonyl group (C=O) attached to an amine group (NH2).

### Step 2: Understand the Desired Product
The target product is ethanamine, which has the structure CH3CH2NH2. This compound is an amine with a two-carbon chain.

### Step 3: Choose the Correct Reagent
Among the options provided, lithium aluminium hydride (LiAlH4) is a reducing agent that can effectively reduce amides to amines.

### Step 4: Mechanism of Reduction
When acetamide is treated with LiAlH4, the reducing agent donates hydrogen to the carbonyl carbon. The reaction proceeds as follows:

1. **Reduction of the Carbonyl Group**: The carbonyl oxygen (C=O) is reduced, and a hydrogen atom is added to the carbon, converting the carbonyl group into a methylene group (CH2).

2. **Formation of the Amine**: The nitrogen atom in the amide retains its hydrogen, and the overall structure transforms from CH3CO NH2 to CH3CH2NH2.

### Step 5: Final Product
After the reduction, we obtain ethanamine (CH3CH2NH2), which is the desired product.

### Conclusion
Therefore, the reagent that will convert acetamide to ethanamine is lithium aluminium hydride (LiAlH4).

---