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Saturday, 31 October

JEE Main · Chemistry · Organic Chemistry: Some Basic Principles and Techniques

Ethane and Butane Conformers

JEE Main asked Ethane and Butane Conformers 3 times in 3 of the 108 shifts Lumi analysed, in 2021 and 2022. It belongs to Alkanes and Free Radicals, in Organic Chemistry: Some Basic Principles and Techniques (Chemistry). The longest wait between two years asking it was 1 year. In 2021 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
3
in 3 shifts
Years
2 of 8
First asked
2021
last in 2022
Pattern
Occasional
across the analysed shifts

Questions on this idea a shift, by year

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

00.050.10’170’200.07’210.03’220’230’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 2 in 24 shifts · 2022: 1 in 24 shifts · 2023: 0 in 12 shifts · 2024: 0 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
  • 20240 of 18
  • 20230 of 12
  • 20221 of 24
  • 20212 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: diagram reading.

  • Dihedral angle in staggered conformation
  • Order of potential energy of n-butane conformers

Difficulty

Easy 1Medium 2Hard 0

Every question was multiple choice.

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. 25 Jun 2022, Shift 1 · Q72In the following structures, which one is having staggered conformation with maximum dihedral angle ?EasyDiagram basedHas a figure
  2. 31 Aug 2021, Shift 2 · Q42Arrange the following conformational isomers of n-butane in order of their increasing potential energy : [four Newman projections labelled…MediumDiagram basedHas a figure
  3. 3 Aug 2021, Shift 1 · Q50Which of the following is the most stable conformer?MediumDiagram basedHas a figure

Shifts: 3 Aug 2021, Shift 1, 31 Aug 2021, Shift 2, 25 Jun 2022, Shift 1.

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