Question

The reagent used to prepare amine from amide is:

Hint:

Remember: The Hofmann bromamide reaction converts amides into primary amines with one carbon less than the original amide.

Answer 1

Step 1: Recall the conversion of amides to amines.
Amides are converted to amines (with one carbon less) by the Hofmann bromamide degradation reaction. In this reaction, amides react with bromine and potassium hydroxide (Br$_2$/KOH) to yield primary amines.

Step 2: Analyzing the options.
- (A) HCl/ZnCl$_2$: Used for Friedel–Crafts type reactions, not for converting amides to amines.
- (B) K$_2$Cr$_2$O$_7$/H$_2$SO$_4$: This is an oxidizing mixture, not used for this conversion.
- (C) NaOH/Ca(OH)$_2$: Commonly used in soda lime decarboxylation, not for amide-to-amine conversion.
- (D) Br$_2$/KOH: Correct. This reagent is used in Hofmann bromamide reaction to prepare amines from amides.

Step 3: Conclusion.
Thus, the correct reagent to prepare amines from amides is Br$_2$/KOH.

Final Answer: \[ \boxed{\text{(D) Br$_2$/KOH}} \]