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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceDiagram basedHardMulti-step

JEE Main 31 August 2021, Shift 1, Chemistry Q45

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

The correct order of reactivity of the given chlorides with acetate in acetic acid is :

The figure, in words

Each option is a row of four drawn structures joined by '>' signs; every structure is a six-membered ring with one C=C double bond drawn at the lower right. P: Cl on a ring carbon next to the C=C, and CH3 on the other C=C carbon (drawn hanging below). Q: CH3 on a ring carbon at the top and Cl on the neighbouring ring carbon (right side, next to the C=C). R: Cl on the upper-left ring carbon and CH3 on the upper-right ring carbon (the CH3-bearing carbon next to the C=C). S: CH2Cl on the upper-right ring carbon next to the C=C. Printed orders: option 1 = P > Q > R > S; option 2 = S > Q > P > R; option 3 = Q > P > S > R; option 4 = P > S > R > Q. (Letters P-S are my labels; they are not printed.)
  1. (1)[figure: four drawn structures separated by '>' signs, in the order P > Q > R > S]Official answer
  2. (2)[figure: four drawn structures separated by '>' signs, in the order S > Q > P > R]
  3. (3)[figure: four drawn structures separated by '>' signs, in the order Q > P > S > R]
  4. (4)[figure: four drawn structures separated by '>' signs, in the order P > S > R > Q]

Official answer

Option 1

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. 3 Aug 2021, Shift 2 · Q45Arrange the following halides in the increasing order of their reactivity towards SN1\mathrm{S_N1} reaction mechanism.MediumSingle correctHas 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.