Question

Identify A, B and C in the sequence :

• A. CH₃CH₂CN, CH₃CH₂CH₂NH₂, CH₃CH₂CH₂OH
• B. CH₃CH₂NC, CH₃CH₂OH, CH₃CH₂CH₂NH₂
• C. CH₃CH₂CN, C₂H₅OH, C₂H₅N₂Cl
• D. CH₃CH₂CN, CH₃CH₂NH₂, C₂H₅OH

Answer 1

The Correct Option is A

To identify A, B, and C, let's break down the reaction steps:

Starting compound: The initial compound is CH₃CH₂Br (ethyl bromide), which is undergoing the following reactions.

Step 1: Reaction with KCN (alc):

The reaction with KCN in alcohol will cause a nucleophilic substitution reaction, where the bromine is replaced by a cyanide (CN) group. This gives the product CH₃CH₂CN (ethyl cyanide or propionitrile).

Therefore, A = CH₃CH₂CN.

Step 2: Reaction with LiAlH₄:

The reaction of nitriles with LiAlH₄ (Lithium aluminium hydride) reduces the nitrile group (CN) to an amine group (NH₂).

Therefore, B = CH₃CH₂CH₂NH₂ (ethylamine).

Step 3: Reaction with HNO₂ (Nitrous acid) at 0°C:

The reaction of amines with nitrous acid (HNO₂) at low temperatures leads to diazotization of the amine group and its subsequent replacement by a hydroxyl group. This converts the amine to an alcohol.

Therefore, C = CH₃CH₂CH₂OH (ethanol).

Final Answer:

A = CH₃CH₂CN (ethyl cyanide)

B = CH₃CH₂CH₂NH₂ (ethylamine)

C = CH₃CH₂CH₂OH (ethanol)

Option 1: CH₃CH₂CN, CH₃CH₂CH₂NH₂, CH₃CH₂CH₂OH is the correct answer.