Identify the correct pathway to convert propanoic acid to ethylamine. The reagent represented by A, B and C are
`CH_(3)CH_(2)COOH overset(A)rarr X overset(B)rarr Y overset(C )rarr CH_(2)CH_(2)NH_(2)`

Options

A. `{:(A,B,C),(Ca(OH)_(2),"Heat",Pt//H_(2)):}`
B. `{:(A,B,C),(SOCl_(2),NH_(3),Br_(2)//KOH):}`
C. `{:(A,B,C),(HNO_(2),P+I_(2),LiAlH_(4)):}`
D. `{:(A,B,C),(HCN,NH_(3),Br_(2)//KOH):}`

Answer

To convert propanoic acid (CH₃CH₂COOH) to ethylamine (CH₂CH₂NH₂), we can follow these steps:

### Step 1: Convert Propanoic Acid to Acid Chloride
- **Reaction**: Propanoic acid reacts with thionyl chloride (SOCl₂).
- **Equation**:
\[ \text{CH}_3\text{CH}_2\text{COOH} \xrightarrow{A} \text{CH}_3\text{CH}_2\text{COCl} \]
- **Explanation**: The hydroxyl group (-OH) of propanoic acid is replaced by a chlorine atom, forming propanoyl chloride.

### Step 2: Convert Acid Chloride to Amide
- **Reaction**: The acid chloride reacts with ammonia (NH₃).
- **Equation**:
\[ \text{CH}_3\text{CH}_2\text{COCl} \xrightarrow{B} \text{CH}_3\text{CH}_2\text{CONH}_2 \]
- **Explanation**: The chlorine atom is replaced by an amine group (-NH₂), forming propanamide.

### Step 3: Convert Amide to Ethylamine
- **Reaction**: The amide undergoes hydrolysis in the presence of bromine (Br₂) and potassium hydroxide (KOH).
- **Equation**:
\[ \text{CH}_3\text{CH}_2\text{CONH}_2 \xrightarrow{C} \text{CH}_2\text{CH}_2\text{NH}_2 \]
- **Explanation**: The amide is converted to ethylamine through a reaction that involves the removal of the carbonyl group and the formation of ethylamine.

### Summary of Reagents
- **A**: SOCl₂ (Thionyl chloride)
- **B**: NH₃ (Ammonia)
- **C**: Br₂ and KOH (Bromine and Potassium Hydroxide)

### Final Answer
The correct pathway is:
- A = SOCl₂
- B = NH₃
- C = Br₂, KOH

Thus, the answer is option number 2.

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