Test: Preparation of Amines (February 27) - NEET MCQ

The correct answer is option C
CH_3​CH₂​CONH₂​ (A)⟶ CH₃​ − CH₂ ​− NH₂​ (B)⟶ ​CH_3​ − CH₂ ​− OH
In the above sequence A & B respectively are Br₂​/KOH and HNO₂​
The first step is Hoffmann bromamide degradation reaction in which an amide (propanamide) is converted to an amine  (ethylamine) containing one carbon atom less. The reagent A is bromine in presence of KOH. In the second step, aliphatic primary amine (ethyl amine) reacts with nitrous acid (reagent B) to form aliphatic primary alcohol (ethyl alcohol).
 

Fe + HCl is preferred due to the following reasons:
- Scrap iron i.e Fe is cheap and commercially easily available
- FeCl₂ formed will get hydrolysed and release HCl, so, HCl which is required in the reaction will be produced by itself
- Hence only small amount of HCl is required to initiate the reaction.

Aniline is prepared commercially by the catalytic hydrogenation of nitrobenzene or by the action of ammonia on chlorobenzene. The reduction of nitrobenzene can also be carried out with iron borings in aqueous acid. A primary aromatic amine, aniline is a weak base and forms salts with mineral acids.

The correct answer is option A
Reduction with LiAlH₄

 

The correct answer is Option D.

Hoffmann Bromamide reaction is Treatment of alkylamide with KOH and Bromine gas which converts it into alkylamine with one less carbon atom, this reaction is generally helpful in converting Carboxylic acids to amines with one less carbon atom . For reaction you may refer to internet but i can give you a hint .

Acetamide + KOH + Bromine gas —-> Alkylamine+ KBr + K2CO3 + H20 ( not sure about the products)

The correct answer is option D
The chemical reaction used for transforming primary alkyl halides into primary amines is called Gabriel phthalimide synthesis. It uses potassium phthalimide. Therefore, Gabriel phthalimide synthesis is used in the preparation of 1o
amide.

LiAlH₄ reduces all oxiginated functional groups to alcohol and all nitrogenated functional groups to amine thus cyanide is a nitrogenated functional group and to convert cyanide to amine LiAlH4 can be used.