Question

The reagent which is used to distinguish \(\mathrm{C_6H_5N(CH_3)_2}\) and \(\mathrm{(C_2H_5)_2NH}\) is

• A. \(\mathrm{C_6H_5SO_2Cl}\)
• B. Anhyd. \(\mathrm{ZnCl_2}\) + conc. \(\mathrm{HCl}\)
• C. \(\mathrm{CrO_3/H_2SO_4}\)
• D. \(\mathrm{CHCl_3}\) + alc. \(\mathrm{KOH}\)

Hint:

Hinsberg reagent: \[ \boxed{\mathrm{C_6H_5SO_2Cl}} \] is used to distinguish primary, secondary and tertiary amines. \[ \boxed{ \begin{aligned} 1^\circ &: \text{Soluble sulphonamide} 2^\circ &: \text{Insoluble sulphonamide} 3^\circ &: \text{No reaction} \end{aligned} } \]

Answer 1

The Correct Option is A

Step 1: Identify the nature of the amines. \[ \mathrm{C_6H_5N(CH_3)_2} \] is a tertiary amine, whereas \[ \mathrm{(C_2H_5)_2NH} \] is a secondary amine.

Step 2: Recall Hinsberg's test. Hinsberg's reagent is \[ \boxed{\mathrm{C_6H_5SO_2Cl}.} \] A secondary amine reacts with Hinsberg's reagent to form an insoluble sulphonamide. A tertiary amine does not react with Hinsberg's reagent. Hence, these two amines can be distinguished using \[ \boxed{\mathrm{C_6H_5SO_2Cl}.} \]

Step 3: Choose the correct option. Therefore, the correct option is \[ \boxed{(A).} \]