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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 31 August 2021, Shift 2, Chemistry Q41

Question 41 of 90 in this shift, Chemistry question 11 of 30, Section A.

The major product of the following reaction is : [reaction: starting material drawn as a five-membered ring; reagent above/below arrow: NaOH / C2H5OH; Major Product]

The figure, in words

Starting material: five-membered carbocycle; CH3 on the top-left ring carbon, Cl on the adjacent ring carbon (right), one C=C double bond drawn at the bottom of the ring. Arrow labelled NaOH over C2H5OH, then 'Major Product'. Options 1-4 are drawn structures (see option text).
  1. (1)[figure: five-membered ring with one C=C double bond (left side); CH3 and OH both attached to the same ring carbon on the right]
  2. (2)[figure: five-membered ring with two C=C double bonds, CH3 on a ring carbon]Official answer
  3. (3)[figure: five-membered ring with one C=C double bond, CH3 on one ring carbon and OH on the adjacent ring carbon]
  4. (4)[figure: five-membered ring with one C=C double bond, CH3 on one ring carbon and HO on another ring carbon]

Official answer

Option 2

NTA final key.

Chapter
Haloalkanes and Haloarenes
Topic
Alkenes and Alkynes
Idea tested
Saytzeff vs. Hofmann Elimination

Same idea in other shifts

Asked 7× in all
  1. 2 Apr 2025, Shift 2 · Q75Consider the above sequence of reactions. 151 g of 2-bromopentane is made to react. Yield of major product P is 80% whereas Q is 100%.…MediumNumerical valueHas a figure
  2. 5 Apr 2024, Shift 2 · Q77Identify the major product in the following reaction. 1-bromo-1-methylcyclopentane…EasyDiagram basedHas a figure
  3. 25 Jun 2022, Shift 1 · Q75The major product in the reaction [figure: CH3−C(CH3)(CH3)−Cl\mathrm{CH_3-C(CH_3)(CH_3)-Cl} (central C with CH3\mathrm{CH_3} above, CH3\mathrm{CH_3} below,…EasySingle correctHas a figure
  4. 2 Sep 2020, Shift 2 · Q44The major product obtained from E2\mathrm{E_2}-elimination of 3-bromo-2-fluoropentane is :HardSingle correctHas a figure
  5. 2 Apr 2017 (offline) · Q52Which of the following, upon treatment with *tert*-BuONa followed by addition of bromine water, fails to decolourize the colour of bromine ?HardSingle correctHas a figure
  6. 2 Apr 2017 (offline) · Q56The major product obtained in the following reaction is : [reaction: (+)-C6H5CH(Br)CH2C6H5\mathrm{C_6H_5CH(Br)CH_2C_6H_5} (Br on wedge, H on hash at the…MediumSingle correctHas 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.