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Saturday, 31 October

JEE Main 2022 · ChemistryMultiple choiceDiagram basedEasyConceptual

JEE Main 25 June 2022, Shift 1, Chemistry Q72

Question 72 of 90 in this shift, Chemistry question 12 of 30, Section A.

In the following structures, which one is having staggered conformation with maximum dihedral angle ?

The figure, in words

Four Newman-projection drawings (circle, with bonds and labelled substituents), one per option.
  1. (1)[figure: Newman projection (circle with three bonds meeting at the centre and three bonds from the circle). Labels as drawn: CH3\mathrm{CH_3} at top, H at upper left, CH3\mathrm{CH_3} at upper right, H at lower left, H at lower right, H at bottom]
  2. (2)[figure: Newman projection. Labels as drawn: CH3\mathrm{CH_3} and H next to each other at top, H at left, H at lower left, H at lower right, CH3\mathrm{CH_3} at bottom right]
  3. (3)[figure: Newman projection. Labels as drawn: CH3\mathrm{CH_3} at top, H at upper left, H at upper right, H at lower left, H at lower right, CH3\mathrm{CH_3} at bottom]Official answer
  4. (4)[figure: Newman projection. Labels as drawn: CH3\mathrm{CH_3} and CH3\mathrm{CH_3} next to each other at top, H at left, H at lower left, H at lower right, H at bottom right]

Official answer

Option 3

NTA final key.

Chapter
Organic Chemistry: Some Basic Principles and Techniques
Topic
Alkanes and Free Radicals
Idea tested
Ethane and Butane Conformers

Same idea in other shifts

Asked 3× in all
  1. 3 Aug 2021, Shift 1 · Q50Which of the following is the most stable conformer?MediumDiagram 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

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.