`Ph-overset(O)overset(||)C-NH_2overset(POCl_3)rarr(A),` Product (A) is

Options

A. `Ph-NH_2`
B. `Ph-CH_2-NH_2`
C. `Ph-overset(OH)overset(|)(CH)-NH_2`
D. `Ph-C-=N`

Answer

To solve the problem, we need to determine the product (A) formed when the compound `Ph-C(=O)-NH2` reacts with `POCl3`. Here’s a step-by-step breakdown of the reaction:

### Step 1: Identify the Reactant
The reactant is `Ph-C(=O)-NH2`, which consists of a phenyl group (Ph), a carbonyl group (C=O), and an amine group (NH2).

### Step 2: Understand the Role of POCl3
Phosphoryl chloride (POCl3) is a reagent that can facilitate the conversion of amides to nitriles. In this case, it will help in the dehydration of the amide to form a nitrile.

### Step 3: Resonance Stabilization
The lone pair of electrons on the nitrogen atom (NH2) can participate in resonance with the carbonyl group. This resonance will stabilize the molecule and prepare it for the next step.

### Step 4: Formation of the Intermediate
Upon treatment with POCl3, the nitrogen's lone pair can attack the carbonyl carbon, leading to the formation of an intermediate. This intermediate will have a positive charge on the nitrogen due to the donation of its lone pair.

### Step 5: Elimination of Chloride Ion
The resonance structure allows for the elimination of a chloride ion (Cl-) from the intermediate. This occurs as the carbonyl group transforms into a good leaving group.

### Step 6: Formation of the Nitrile
After the chloride ion leaves, the nitrogen atom will lose a hydrogen atom (H) and form a triple bond with the carbon atom. This results in the formation of a nitrile.

### Step 7: Final Product
The final product (A) is `Ph-C≡N`, which is a phenyl nitrile. The by-products of the reaction include HCl and PO.

### Conclusion
The product (A) formed from the reaction of `Ph-C(=O)-NH2` with `POCl3` is `Ph-C≡N`.

### Summary of Steps:
1. Identify the reactant.
2. Understand the role of POCl3.
3. Consider resonance stabilization.
4. Form an intermediate.
5. Eliminate chloride ion.
6. Form the nitrile.
7. Conclude with the final product.