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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 31 August 2021, Shift 1, Chemistry Q43

Question 43 of 90 in this shift, Chemistry question 13 of 30, Section A.

Choose the correct name for compound given below :

The figure, in words

Skeletal drawing: a horizontal line on the left containing a triple bond (three parallel lines) joined to a vertex; from that vertex a double bond goes up and to the right to a carbon; that carbon carries Br (to the right, horizontal bond) and a single bond going up-left.
  1. (1)(4E)-5-Bromo-hex-4-en-2-yne
  2. (2)(2E)-2-Bromo-hex-2-en-4-yneOfficial answer
  3. (3)(2E)-2-Bromo-hex-4-yn-2-ene
  4. (4)(4E)-5-Bromo-hex-2-en-4-yne

Official answer

Option 2

NTA final key.

Chapter
Organic Chemistry: Some Basic Principles and Techniques
Topic
IUPAC Nomenclature
Idea tested
Alkene vs Alkyne Numbering Tiebreaker

Same idea in other shifts

Asked 2× in all
  1. 4 Apr 2025, Shift 2 · Q64The IUPAC name of the following compound is : HC≡C−CH2−CH(OH)−CH2−CH=CH2\mathrm{HC\equiv C-CH_2-CH(OH)-CH_2-CH=CH_2}MediumSingle correct

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.