Match List-I with List-II
|
List-I |
List-II |
|
(A) \( S_N1 \) Reaction |
(I) vic-dibromides |
|
(B) Bromination of alkenes |
(II) gem-dihalides |
|
(C) Alkylidene halides |
(III) racemisation |
|
(D) Elimination of HX from alkylhalide |
(IV) Saytzeff rule |
Choose the correct answer from the options given below.
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → (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 (dehydrohalogenation).
(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-dibromides. \( \ce{Br2} \) adds across the C=C bond, putting Br on adjacent carbons.
\( \ce{CH2=CH2 + Br2 -> BrCH2-CH2Br} \)
(C) Alkylidene halides — This matches (II) gem-dihalides. Alkylidene halides have both halogens on the same carbon, e.g. \( \ce{CH3CHBr2} \) (ethylidene bromide).
(D) Elimination of HX from alkylhalide — 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 | – |