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Saturday, 31 October

JEE Main · Chemistry · Hydrocarbons

Allylic Halogenation with NBS

JEE Main asked Allylic Halogenation with NBS 3 times in 3 of the 108 shifts Lumi analysed, in 2021, 2022 and 2024. It belongs to Alkenes and Alkynes, in Hydrocarbons (Chemistry). The longest wait between two years asking it was 2 years.

Updated 2026-10-24

Times asked
3
in 3 shifts
Years
3 of 8
First asked
2021
last in 2024
Pattern
Comes in cycles
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2021, 2022 and 2024. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.050.10’170’200.03’210.03’220’230.05’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 1 in 24 shifts · 2022: 1 in 24 shifts · 2023: 0 in 12 shifts · 2024: 1 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20260 of 9
  • 20250 of 8
  • 20241 of 18
  • 20230 of 12
  • 20221 of 24
  • 20211 of 24
  • 20200 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Diagram based is the usual form. Skill tested: application.

  • Predict product of reaction
  • Reagent identification

Difficulty

Easy 0Medium 3Hard 0

1 of the 3 questions had a numerical answer.

Every question

All 3 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 29 Jan 2024, Shift 1 · Q74Identify product A and product B :MediumDiagram basedHas a figure
  2. 28 Jun 2022, Shift 2 · Q89The major product of the following reaction contains __________ bromine atom(s). [reaction: structure →hνBr2\xrightarrow[h\nu]{\mathrm{Br_2}}…MediumNumerical valueHas a figure
  3. 16 Mar 2021, Shift 2 · Q44[figure: cyclohexene reacts with reagent A to give 1,4-dichlorocyclohex-2-ene (a cyclohexene ring with Cl on the two ring carbons para to…MediumDiagram basedHas a figure

Shifts: 16 Mar 2021, Shift 2, 28 Jun 2022, Shift 2, 29 Jan 2024, Shift 1.

Same topic

Other ideas in Alkenes and Alkynes

Alkenes and Alkynes has 24 ideas JEE Main has asked; 14 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas