MCQEasyJEE 2025Reaction Mechanisms (Substitution, Addition, Elimination)

JEE Chemistry 2025 Question with Solution

Match the LIST-I with LIST-II

Table with LIST-I and LIST-II. LIST-I: A. Carbocation, B. C-Free radical, C. Nucleophile, D. Electrophile. LIST-II: I. Species that can supply a pair of electrons, II. Species that can receive a pair of electrons, III. $$\text{sp}^2$$ hybridized carbon with empty $$p$$-orbital, IV. $$\text{sp}^2/\text{sp}^3$$ hybridized carbon with one unpaired electron.

Choose the correct answer from the options given below:

  • A

    A-III, B-III, C-I, D-IV

  • B

    A-III, B-IV, C-II, D-I

  • C

    A-IV, B-II, C-III, D-I

  • D

    A-III, B-IV, C-I, D-II

Answer

Correct answer:D

Step-by-step solution

Standard Method

Given: LIST-I contains Carbocation, C-Free radical, Nucleophile and Electrophile. LIST-II contains their definitions or characteristics.

Find: The correct matching between LIST-I and LIST-II.

A carbocation is a positively charged carbon species. It is electron deficient and has an empty pp-orbital. Therefore, A (Carbocation) matches III.

A C-Free radical has one unpaired electron. Such a carbon species can be described as sp2/sp3\text{sp}^2/\text{sp}^3 hybridized with one unpaired electron. Therefore, B (C-Free radical) matches IV.

A nucleophile donates a pair of electrons. Therefore, C (Nucleophile) matches I.

An electrophile accepts a pair of electrons because it is electron deficient. Therefore, D (Electrophile) matches II.

So the correct matching is:

  • A - III
  • B - IV
  • C - I
  • D - II

Therefore, the correct option is D.

Definition-Based Matching

Given:

  • Carbocation
  • C-Free radical
  • Nucleophile
  • Electrophile

Find: Which description in LIST-II corresponds to each species.

Key ideas:

  • Carbocation: sp2\text{sp}^2, planar, electron deficient, empty pp-orbital
  • Free radical: one unpaired electron
  • Nucleophile: electron-pair donor
  • Electrophile: electron-pair acceptor

Now match one by one:

  1. Carbocation corresponds to sp2\text{sp}^2 hybridized carbon with empty pp-orbital, so A - III.
  2. C-Free radical corresponds to sp2/sp3\text{sp}^2/\text{sp}^3 hybridized carbon with one unpaired electron, so B - IV.
  3. Nucleophile corresponds to species that can supply a pair of electrons, so C - I.
  4. Electrophile corresponds to species that can receive a pair of electrons, so D - II.

Hence the final matching is A-III, B-IV, C-I, D-II, so the correct option is D.

Common mistakes

  • Confusing nucleophile with electrophile. A nucleophile donates an electron pair, while an electrophile accepts an electron pair. Match them using electron-pair donation and acceptance, not by memorizing names alone.

  • Matching carbocation with the free-radical description. A carbocation has an empty pp-orbital and is electron deficient, whereas a free radical has one unpaired electron. Check whether the species has a positive charge or an unpaired electron.

  • Assuming C-Free radical must always be only sp2\text{sp}^2 hybridized. The listed description explicitly allows sp2/sp3\text{sp}^2/\text{sp}^3 hybridization with one unpaired electron. Use the given statement in LIST-II carefully.

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