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Match each electronic-effect description in Column-I with the correct group in Column-II. Column-I: (A) Donates electrons inductively (+I) but neither donates nor withdraws by resonance (B) Withdraws electrons inductively (-I) but neither donates nor withdraws by resonance (C) Withdraws electrons inductively (-I) and donates electrons by resonance (+R) (D) Withdraws electrons inductively (-I) and withdraws electrons by resonance (-R) Column-II: (P) -OH (Q) -NO2 (R) -CH2-CH3 (S) -NH3+ (T) -NH2 Choose the correct matching.

1. A-R, B-S, C-P, D-Q
2. A-P, B-S, C-T, D-Q
3. A-R, B-Q, C-P, D-S
4. A-S, B-R, C-T, D-Q

Correct answer: A-R, B-S, C-P, D-Q

Solution

(A) -CH2CH3 (ethyl, R) is a saturated alkyl group: it pushes electrons inductively (+I) and has no lone pair or pi system, so no resonance effect => A-R. (B) -NH3+ (S) is a saturated, positively charged group: strong -I, and the nitrogen has no lone pair left for resonance => B-S. (C) -OH (P): oxygen is more electronegative than carbon so it shows -I, but its lone pairs are donated into the ring (+R) => C-P. (Note: -NH2 also fits +R with -I, but the cleaner, unambiguous slot for the listed set is -OH; -NH2 (T) is the strongest +R donor and is the spare option.) (D) -NO2 (Q): strongly electron-withdrawing both inductively (-I) and by resonance (-R) => D-Q. Correct matching: A-R, B-S, C-P, D-Q.

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