A compound (X) having the molecfular formula `C_(3)H_(9)N` reacts with benzenesulphonyl chloride to form a solild insoluble in alkali is . The compound (X) is

Options

A. `CH_(3)CH_(2)CH_(2)NH_(2)`
B. `(CH_(3))_(2)CHNH_(2)`
C. `CH_(3)CH_(2)NHCH_(3)`
D. `(CH_(3))3)N`

Answer

To solve the problem, we need to identify the compound (X) with the molecular formula C3H9N that reacts with benzene sulphonyl chloride to form a solid that is insoluble in alkali. Let's break down the solution step by step.

### Step 1: Identify the Type of Amine
The molecular formula C3H9N suggests that the compound (X) is an amine. Amines can be classified into primary (1°), secondary (2°), and tertiary (3°) amines based on the number of carbon groups attached to the nitrogen atom.

**Hint:** Remember that primary amines have one alkyl group and two hydrogen atoms attached to nitrogen, secondary amines have two alkyl groups and one hydrogen, and tertiary amines have three alkyl groups and no hydrogen.

### Step 2: Analyze the Reaction with Benzene Sulphonyl Chloride
Benzene sulphonyl chloride (C6H5SO2Cl) reacts with amines to form sulphonamides. The reaction requires the presence of a hydrogen atom on the nitrogen, which is available in primary and secondary amines but not in tertiary amines.

**Hint:** The presence of a hydrogen atom on the nitrogen is crucial for the reaction to occur.

### Step 3: Consider the Possible Structures
1. **Primary Amine (1°)**: If (X) is a primary amine, it could be propylamine (C3H9N), which has the structure CH3-CH2-CH2-NH2.
2. **Secondary Amine (2°)**: If (X) is a secondary amine, it could be N-methyl ethylamine (C2H5-NH-CH3) or similar structures.

**Hint:** Draw the structures of possible amines to visualize the reaction.

### Step 4: Determine the Product of the Reaction
When a primary amine reacts with benzene sulphonyl chloride, it forms a sulphonamide. The product of the reaction with a primary amine will have an acidic hydrogen due to the sulphonamide group (R-NH-SO2-C6H5), making it soluble in alkali.

For a secondary amine, the product will lack acidic hydrogen (as it has no hydrogen attached to nitrogen), making it insoluble in alkali.

**Hint:** Consider the solubility of the products formed from primary and secondary amines.

### Step 5: Conclusion
Since the question states that the product is insoluble in alkali, the compound (X) must be a secondary amine. The only secondary amine that fits the molecular formula C3H9N is N-ethyl-N-methylamine.

Thus, the compound (X) is **N-ethyl-N-methylamine**.

**Final Answer:** The compound (X) is N-ethyl-N-methylamine.