JEE Main · 2021 · Shift-IImediumGOC-087

Which compound does NOT exhibit resonance?

General Organic Chemistry (GOC) · Class 11 · JEE Main Previous Year Question

Question

Which compound does NOT exhibit resonance?

Options
  1. a

    CH₃CH₂CH₂CONH₂

  2. b

    CH₃CH₂CH=CHCH₂NH₂

  3. c

    CH₃CH₂OCH=CH₂

  4. d

    Benzyl alcohol

Correct Answerb

CH₃CH₂CH=CHCH₂NH₂

Detailed Solution

Step 1: Identifying Resonance Resonance occurs when multiple Lewis structures can be drawn due to delocalized electrons (lone pairs adjacent to pi bonds or pi bonds in conjugation).

  • (A) Amide: lone pair on Nitrogen is in conjugation with C=OC=O. (Resonance present)
  • (B) Allylic amine: The lone pair is on a carbon far from the double bond (homoallylic-like). There is no conjugation. (Resonance absent)
  • (C) Vinyl ether: lone pair on Oxygen is in conjugation with C=CC=C. (Resonance present)
  • (D) Benzyl alcohol: lone pair on Oxygen is not in conjugation with the ring (separated by sp3sp^3 carbon), but the ring itself has resonance.

Step 2: Conclusion In (B), the amine group is too far from the double bond for any resonance stabilization.

Answer: (b)\boxed{\text{Answer: (b)}},

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