The final product (C ) obtained in the reaction sequence is
`CH_(3)CH_(2)COOH overset(PCl_(3))to(A)overset(C_(6)H_(6))underset(AlCl_(3))to(B)overset(NH_(2)NH_(2))underset("base, heat")to(C )`

Options

A.
B.
C.
D.

Explanation

To solve the given reaction sequence, we will go through each step systematically.

### Step 1: Reaction of Propanoic Acid with PCl3
The first step involves the reaction of propanoic acid (CH₃CH₂COOH) with phosphorus trichloride (PCl₃).

**Reaction:**
\[ \text{CH}_3\text{CH}_2\text{COOH} + \text{PCl}_3 \rightarrow \text{CH}_3\text{CH}_2\text{C(=O)Cl} + \text{HCl} + \text{POCl}_3 \]

**Product A:**
The product formed is propanoyl chloride (CH₃CH₂C(=O)Cl).

### Step 2: Friedel-Crafts Acylation
Next, we take the product A (propanoyl chloride) and react it with benzene (C₆H₆) in the presence of anhydrous aluminum chloride (AlCl₃). This reaction is known as Friedel-Crafts acylation.

**Reaction:**
\[ \text{CH}_3\text{CH}_2\text{C(=O)Cl} + \text{C}_6\text{H}_6 \xrightarrow{\text{AlCl}_3} \text{C}_6\text{H}_5\text{C(=O)CH}_2\text{CH}_3 + \text{HCl} \]

**Product B:**
The product formed is phenyl propanoyl (C₆H₅C(=O)CH₂CH₃).

### Step 3: Hydrazine Reaction
In the final step, we react product B (phenyl propanoyl) with hydrazine (NH₂NH₂) in the presence of a base and heat. This reaction is known as the Wolff-Kishner reduction.

**Reaction:**
\[ \text{C}_6\text{H}_5\text{C(=O)CH}_2\text{CH}_3 + \text{NH}_2\text{NH}_2 \xrightarrow{\text{Base, Heat}} \text{C}_6\text{H}_5\text{CH}_2\text{CH}_3 + \text{N}_2 + \text{H}_2\text{O} \]

**Product C:**
The final product C is phenyl ethane (C₆H₅CH₂CH₃).

### Summary of Products:
- Product A: Propanoyl chloride (CH₃CH₂C(=O)Cl)
- Product B: Phenyl propanoyl (C₆H₅C(=O)CH₂CH₃)
- Product C: Phenyl ethane (C₆H₅CH₂CH₃)

### Final Answer:
The final product (C) obtained in the reaction sequence is **C₆H₅CH₂CH₃**.

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