n-Propylamine yields a volatile compound X on warning with alc alkali and chloroform X has an offensive odour. The structure of X is

Options

A. `CH_(3)CH_(2)CH_(2)CN`
B. `(CH_(3))_(2)CHCN`
C. `CH_(3)CH_(2)CH_(2)NC`
D. `(CH_(3))_(2)CHNC`

Answer

To solve the problem, we need to identify the compound X formed when n-propylamine reacts with chloroform and an alcoholic alkali. The steps to derive the structure of compound X are as follows:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactants in this reaction are n-propylamine (C3H9N), chloroform (CHCl3), and an alcoholic alkali (like KOH in alcohol).

2. **Understand the Reaction Mechanism**:
- When n-propylamine is warmed with chloroform and an alcoholic alkali, a reaction known as the "Hofmann degradation" occurs. The chloroform reacts with the amine in the presence of a strong base to form a carbene intermediate.

3. **Formation of Carbene**:
- The chloroform (CHCl3) loses a hydrogen atom and forms a trichloromethyl anion (CCl3^-). This anion can then react with the n-propylamine to form a carbene (CCl2).

4. **Reaction with Carbene**:
- The carbene (CCl2) can react with n-propylamine to form an isocyanide (also known as carbylamine). The general reaction can be represented as:
\[ RNH_2 + CCl_2 \rightarrow RNC + HCl \]
- Here, R represents the n-propyl group (C3H7).

5. **Identify the Product**:
- The product formed is isopropyl isocyanide (or propyl isocyanide), which has the structure:
\[ CH_3-CH_2-CH(NC)-C \]
- Isocyanides are known for their offensive odor, which matches the description given in the question.

6. **Final Structure of Compound X**:
- Therefore, the structure of compound X is:
\[ CH_3-CH_2-CH(NC)-C \]
- This is the isocyanide derived from n-propylamine.

### Conclusion:
The structure of compound X formed from the reaction of n-propylamine with chloroform and alcoholic alkali is propyl isocyanide.