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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceSingle correctMediumConceptual

JEE Main 3 August 2021, Shift 2, Chemistry Q45

Question 45 of 90 in this shift, Chemistry question 15 of 30, Section A.

Arrange the following halides in the increasing order of their reactivity towards SN1\mathrm{S_N1} reaction mechanism.

The figure, in words

Four ring chlorides: (A) chlorocyclohexane; (B) chlorocyclohexene with Cl on a ring C=C carbon (vinylic); (C) cyclohexene ring with Cl and CH3 on the same carbon next to the C=C (tertiary allylic); (D) cyclohexene with Cl on a carbon next to the C=C (secondary allylic).
  1. (1)A<B<D<CA < B < D < C
  2. (2)B<A<D<CB < A < D < COfficial answer
  3. (3)C<D<B<AC < D < B < A
  4. (4)C<D<A<BC < D < A < B

Official answer

Option 2

NTA final key.

Chapter
Haloalkanes and Haloarenes
Topic
SN1 and SN2 Mechanisms
Idea tested
Allylic and Benzylic Reactivity in SN1

Same idea in other shifts

Asked 7× in all
  1. 2 Apr 2026, Shift 1 · Q64Given below are two statements : Statement (I) : Benzyl chloride reacts faster in SN1\mathrm{S_N1} mechanism than ethyl chloride. Statement…EasyTwo statements
  2. 11 Apr 2023, Shift 1 · Q74[figure: Reaction (I): 4-methoxybenzyl chloride (MeO−C6H4−CH2Cl\mathrm{MeO{-}C_6H_4{-}CH_2Cl}) + Nu gives 4-methoxybenzyl-Nu. Reaction (II):…MediumDiagram basedHas a figure
  3. 24 Jun 2022, Shift 2 · Q89Consider the above reaction. The number of π\pi electrons present in the product 'P' is ________.MediumNumerical valueHas a figure
  4. 29 Jun 2022, Shift 2 · Q75Two isomers (A) and (B) with Molar mass 184 g/mol and elemental composition C, 52.2% ; H, 4.9 % and Br 42.9%, respectively on oxidation…HardDiagram basedHas a figure
  5. 31 Aug 2021, Shift 1 · Q45The correct order of reactivity of the given chlorides with acetate in acetic acid is :HardDiagram basedHas a figure
  6. 2 Apr 2017 (offline) · Q55The increasing order of the reactivity of the following halides for the SN1\mathrm{S_N1} reaction is : CH3CHCH2CH3\mathrm{CH_3CHCH_2CH_3} with Cl on…MediumOtherHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.