In order to distinguish between `C_(2)H_(5)NH_(2) and C_(6)H_(5)NH_(2)`, Which of the following reagents(s) is useful?

Options

A. Hinsberg reagent
B. `beta-"napthol"`
C. `CHCl_(3)//KOH`
D. NaOH

Answer

To distinguish between ethylamine (C2H5NH2) and aniline (C6H5NH2), we can follow these steps:

### Step 1: Understand the Compounds
- Ethylamine (C2H5NH2) is a primary aliphatic amine.
- Aniline (C6H5NH2) is a primary aromatic amine.

### Step 2: Identify the Reagents
We need to choose a reagent that can differentiate between these two types of amines. The options given are:
1. Hinsberg reagent
2. Beta-naphthol
3. CHCl3/KOH
4. NaOH

### Step 3: Analyze the Reagents
- **Hinsberg Reagent**: This reagent can react with both amines to form sulfonamides, but it does not distinguish between them.

- **Beta-naphthol**: When aniline is diazotized and reacted with beta-naphthol, it forms a colored azo dye. Ethylamine does not form a similar dye. This is a distinguishing test.

- **CHCl3/KOH**: This is used in the carbylamine test, which can indicate the presence of primary amines but does not distinguish between ethylamine and aniline.

- **NaOH**: This base does not provide a distinguishing reaction between the two amines.

### Step 4: Conclusion
The only reagent that can effectively distinguish between ethylamine and aniline is beta-naphthol, as it leads to the formation of a dye with aniline but not with ethylamine.

### Final Answer
The useful reagent to distinguish between C2H5NH2 (ethylamine) and C6H5NH2 (aniline) is **Beta-naphthol**.

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