`C_2H_5NH_2 overset(HNO_2)to A overset(PCl_5)to B overset(NH_3)to C `
The compound C is identified as

Options

A. acetamide
B. ethylamine
C. ethyl cyanide
D. methyl amine

Explanation

To solve the problem step by step, we will analyze the reactions that occur when ethylamine (C2H5NH2) is treated with HNO2, PCl5, and NH3.

### Step 1: Reaction of Ethylamine with HNO2
- **Reaction**: Ethylamine (C2H5NH2) is treated with nitrous acid (HNO2).
- **Process**: This reaction leads to the formation of a diazonium salt. However, since ethylamine is a primary amine, the diazonium salt formed is unstable and will undergo hydrolysis.
- **Product A**: The hydrolysis of the diazonium salt results in the formation of ethanol (C2H5OH).

### Step 2: Reaction of Ethanol with PCl5
- **Reaction**: The ethanol (C2H5OH) is then treated with phosphorus pentachloride (PCl5).
- **Process**: PCl5 is used to convert the alcohol (OH group) into an alkyl halide (Cl group). The chlorine atom replaces the hydroxyl group.
- **Product B**: The product of this reaction is ethyl chloride (C2H5Cl).

### Step 3: Reaction of Ethyl Chloride with Ammonia
- **Reaction**: Ethyl chloride (C2H5Cl) is treated with ammonia (NH3).
- **Process**: In this step, ammonia acts as a nucleophile and attacks the carbon atom bonded to the chlorine atom in ethyl chloride. This is an SN2 reaction where the chlorine atom is displaced.
- **Product C**: The final product after the reaction with ammonia is ethylamine (C2H5NH2).

### Final Answer
The compound C is identified as **Ethylamine (C2H5NH2)**.

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