What is the end product in the following sequence of reactions?
`C_(2)H_(5)NH_(2) overset(HNO_(2))to A underset(PCl_(2))to B underset(NH_(3))to C`

Options

A. Ethylcyanide
B. Ethylamine
C. Methylamine
D. Acetamide

Answer

To determine the end product of the given sequence of reactions, we will analyze each step carefully:

### Step 1: Reaction of C2H5NH2 with HNO2
- **Starting Compound**: Ethylamine (C2H5NH2)
- **Reagent**: Nitrous acid (HNO2)

When ethylamine reacts with nitrous acid, the amine group (-NH2) is converted into a hydroxyl group (-OH) and nitrogen gas (N2) is evolved. The reaction can be summarized as follows:

\[ C2H5NH2 + HNO2 \rightarrow C2H5OH + N2 + H2O \]

- **Product A**: Ethanol (C2H5OH)

### Step 2: Reaction of A (C2H5OH) with PCl2
- **Starting Compound**: Ethanol (C2H5OH)
- **Reagent**: Phosphorus trichloride (PCl3)

When ethanol reacts with phosphorus trichloride, it undergoes a substitution reaction where the hydroxyl group (-OH) is replaced by a chlorine atom (-Cl). The balanced reaction is:

\[ C2H5OH + PCl3 \rightarrow C2H5Cl + H3PO3 \]

- **Product B**: Ethyl chloride (C2H5Cl)

### Step 3: Reaction of B (C2H5Cl) with NH3
- **Starting Compound**: Ethyl chloride (C2H5Cl)
- **Reagent**: Ammonia (NH3)

In this step, ethyl chloride reacts with ammonia, leading to the substitution of the chlorine atom with an amine group (-NH2). The reaction can be represented as:

\[ C2H5Cl + NH3 \rightarrow C2H5NH2 + NH4Cl \]

- **Product C**: Ethylamine (C2H5NH2)

### Final Answer
The end product of the sequence of reactions is **ethylamine (C2H5NH2)**.

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