JEE Main · 2025 · Shift-IImediumGOC-036

Given below are two statements: Statement I: Hyperconjugation is not a permanent effect. Statement II: In general,…

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

Question

Given below are two statements:

Statement I: Hyperconjugation is not a permanent effect. Statement II: In general, greater the number of alkyl groups attached to a positively charged C-atom, greater is the hyperconjugation interaction and stabilization of the cation.

In the light of the above statements, choose the correct answer:

Options
  1. a

    Statement I true but Statement II false

  2. b

    Both Statement I and Statement II are false

  3. c

    Statement I false but Statement II true

  4. d

    Both Statement I and Statement II are true

Correct Answerc

Statement I false but Statement II true

Detailed Solution

Step 1: Understanding Hyperconjugation Hyperconjugation (no-bond resonance) involves the delocalization of σ\sigma-electrons of \ceCH\ce{C-H} bond of an alkyl group directly attached to an atom of unsaturated system or to an atom with an unshared pp-orbital. It is a permanent effect.

Step 2: Evaluating Statements

  • Statement I: "Hyperconjugation is a temporary effect." (False - It is permanent).
  • Statement II: "The more the number of alkyl groups attached to a carbocation, the greater is the stabilization." (True - More α\alpha-hydrogens increase hyperconjugative structures).

Answer: (c) I: False, II: True\boxed{\text{Answer: (c) I: False, II: True}}

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