Consider the following sequence of reactions:
`PhCO_(2)H underset(2. NH_(3))overset(1. PCk_(5))rarr A underset(2. H_(2)//Ni)overset(1. P_(4)O_(10). "heat")rarrB`. The final product (B) is:

Options

A. benzonitrile
B. benzlamine
C. aniline
D. benzamide

Explanation

To determine the final product (B) from the given sequence of reactions, let's break down the steps involved:

### Step 1: Identify the Starting Material
The starting material is benzoic acid (PhCO₂H), which has the structure:
```
O
||
Ph-C-OH
```

### Step 2: Reaction with Ammonia
The first reaction involves treating benzoic acid with ammonia (NH₃) in the presence of phosphorus pentachloride (PCl₅). PCl₅ converts the carboxylic acid group into an amide group. The reaction can be represented as:
```
PhCO₂H + NH₃ → PhCONH₂ (Benzamide)
```
So, the product A is benzamide (PhCONH₂).

### Step 3: Reaction with P₄O₁₀ and Heat
Next, benzamide (A) is heated with phosphorus pentoxide (P₄O₁₀). This reaction leads to the formation of a nitrile (in this case, benzonitrile). The reaction can be represented as:
```
PhCONH₂ + P₄O₁₀ + heat → PhC≡N (Benzonitrile)
```

### Step 4: Hydrogenation
The final step involves hydrogenating benzonitrile (PhC≡N) using hydrogen gas (H₂) in the presence of nickel (Ni) as a catalyst. This reaction converts the nitrile group into an amine group:
```
PhC≡N + H₂ → PhCH₂NH₂ (Benzylamine)
```
Thus, the final product B is benzylamine (PhCH₂NH₂).

### Final Product
The final product (B) is benzylamine.

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