Match List - I with List - II.
| List - I | List - II |
| (A) \(S_N1\) reaction | (I) vic-dibromide |
| (B) Bromination of alkenes | (II) gem-dibromide |
| (C) Alkylidene halides | (III) Racemisation |
| (D) Dehydrohalogenation of haloalkanes | (IV) Saytzeff rule |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (A)-(III), (B)-(I), (C)-(II), (D)-(IV)
Each item is a term from the chemistry of haloalkanes: the stereochemistry of SN1, the product of adding a halogen to an alkene, the common name of a dihalide, and the rule for the major product of an elimination.
(A) SN1 reaction — This matches (III) Racemisation. The planar carbocation can be attacked from either face, so an optically active halide gives both enantiomers.
(B) Bromination of alkenes — This matches (I) vic-dibromide. \( \ce{Br2} \) adds across the C=C bond, putting Br on adjacent carbons.
\( \ce{CH2=CH2 + Br2 -> BrCH2-CH2Br} \)
(C) Alkylidene halides — This matches (II) gem-dibromide. Alkylidene halides have both halogens on the same carbon, e.g. \( \ce{CH3CHBr2} \) (ethylidene bromide).
(D) Dehydrohalogenation of haloalkanes — This matches (IV) Saytzeff rule. When two alkenes are possible, the more substituted alkene is the major product.
\( \ce{CH3CH2CHBrCH3} \xrightarrow{\text{alc. }\ce{KOH}} \underset{\text{major}}{\ce{CH3CH=CHCH3}} + \underset{\text{minor}}{\ce{CH3CH2CH=CH2}} \)
Note: The same/similar question has been asked in different years by NTA as per the details given below:
| 2026 | 2025 | 2024 | 2023 | 2022 |
|---|---|---|---|---|
| – | 29-05 S1 | – | 05-06 S1 | – |