Benzamide on treatment with `POCl_3` gives :

Options

A. Aniline
B. Benzonitrile
C. Chlorobenzene
D. Benzyl amine

Answer

To solve the question regarding the reaction of Benzamide with POCl3, we can follow these steps:

### Step 1: Understand the Reactants
Benzamide is an amide derived from benzoic acid, with the structure C6H5CONH2. POCl3, or phosphorus oxychloride, is a reagent often used in organic synthesis, particularly for dehydrating reactions.

**Hint:** Identify the structure of benzamide and understand the role of POCl3.

### Step 2: Identify the Reaction Type
When benzamide reacts with POCl3, it undergoes a dehydration reaction. POCl3 acts as a dehydrating agent, which means it will remove a molecule of water (H2O) from benzamide.

**Hint:** Recall that dehydration reactions often involve the removal of water from a compound.

### Step 3: Predict the Product
During the reaction, the amide group (CONH2) of benzamide is converted into a nitrile group (C≡N). This transformation results in the formation of benzonitrile (C6H5CN).

**Hint:** Consider how the functional groups change during the reaction and what the final product will be.

### Step 4: Write the Balanced Reaction
The balanced chemical equation for the reaction can be represented as follows:

\[ \text{C}_6\text{H}_5\text{CONH}_2 + \text{POCl}_3 \rightarrow \text{C}_6\text{H}_5\text{CN} + \text{by-products} \]

Here, the by-products include phosphorus oxychloride derivatives and possibly HCl.

**Hint:** Ensure that the number of atoms of each element is conserved in the reaction.

### Step 5: Conclusion
From the reaction, we conclude that benzamide, when treated with POCl3, yields benzonitrile as the main product.

**Final Answer:** Benzamide on treatment with POCl3 gives **Benzonitrile**.