Question

Which of the following reactions does not match correctly with its name?

• A. R–CO–NH₂ + Br₂ + 4KOH (aq) → : Hofmann degradation
• B. R–NH₂ + 3R–X → : Hofmann exhaustive alkylation
• C. R–CH₂– N⁺– (R) 3X ^– → ((i) moist Ag₂O, (ii) △, -H₂ O) : Hofmann elimination
• D. R–CO–NH₂ + 4[H] → (LiAlH₄) : Mendius reduction

Answer 1

The Correct Option is C

Solution:

Explanation of the Options:

Option 1: R–CO–NH2 + Br2 + 4KOH (aq) → : Hofmann Degradation

This reaction involves the conversion of an amide (R–CO–NH2) to an amine by removing the carbonyl group. It is known as the Hofmann degradation reaction, which is correctly matched here.

Option 2: R–NH2 + 3R–X → : Hofmann Exhaustive Alkylation

This reaction involves the alkylation of an amine (R–NH2) using an alkyl halide (R–X) in an excess amount. The reaction name Hofmann Exhaustive Alkylation is also correctly matched to this process.

Option 3: R–CH2–N+ (R) 3X– → (i) moist Ag2O, (ii) Δ, (iii) H2O : Hofmann Elimination

This reaction involves the elimination of an amine group from an amine salt (R–CH2–N+). The process is known as the Hofmann elimination reaction, where an amine is removed, resulting in the formation of an alkene. However, this is a wrong match because Hofmann elimination typically involves the removal of the amine group from an amine salt under basic conditions, not with silver oxide (Ag2O) as described here.

Option 4: R–CO–NH2 + [H] → (LiAlH4) : Mendius Reduction

This reaction involves the reduction of an amide (R–CO–NH2) to an amine using a strong reducing agent like lithium aluminum hydride (LiAlH4). The reaction is known as the Mendius reduction, which is a well-known reaction for reducing amides to amines. This is also correctly matched.

Conclusion:

The reaction in Option 3 does not correctly match with its name. The reaction is incorrectly labeled as Hofmann Elimination, but the reagents and conditions listed are not typical for this elimination process. Therefore, the correct answer is:

Option 3: R–CH2–N+ (R) 3X– → (i) moist Ag2O, (ii) Δ, (iii) H2O : Hofmann Elimination