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Saturday, 31 October

JEE Main · Chemistry · Hydrocarbons

Halogenation Chain Mechanism

JEE Main asked Halogenation Chain Mechanism 3 times in 3 of the 108 shifts Lumi analysed, in 2022, 2023 and 2026. It belongs to Alkanes and Free Radicals, in Hydrocarbons (Chemistry). The longest wait between two years asking it was 3 years.

Updated 2026-10-24

Times asked
3
in 3 shifts
Years
3 of 8
First asked
2022
last in 2026
Pattern
Frequent
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2022, 2023 and 2026. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.10.20’170’200’210.03’220.07’230’240’250.11’26

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

Shift by shift

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

  • 20261 of 9
  • 20250 of 8
  • 20240 of 18
  • 20231 of 12
  • 20221 of 24
  • 20210 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.

  • Count dichloro products of alkane
  • Count bromo derivatives of alkane

Difficulty

Easy 0Medium 2Hard 1

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. 8 Apr 2026, Shift 2 · Q65n-Butane on monochlorination under photochemical condition gives an optically active compound "P". "P" on further chlorination gives…MediumSingle correct
  2. 6 Apr 2023, Shift 1 · Q89Number of bromo derivatives obtained on treating ethane with excess of Br2\mathrm{Br_2} in diffused sunlight is ________HardNumerical value
  3. 28 Jun 2022, Shift 2 · Q75A →(ii) CN−; (iii) H2O/H+(i) Cl2, Δ\xrightarrow[\text{(ii) CN}^-\text{; (iii) H}_2\text{O/H}^+]{\text{(i) Cl}_2,\ \Delta} 4-Bromophenyl acetic acid. In the above…MediumDiagram basedHas a figure

Shifts: 28 Jun 2022, Shift 2, 6 Apr 2023, Shift 1, 8 Apr 2026, Shift 2.

Same topic

Other ideas in Alkanes and Free Radicals

Alkanes and Free Radicals has 18 ideas JEE Main has asked; 11 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas