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Friday, 9 October

NEET UG 2021 · Chemistry · Question 63

NEET 2021 Chemistry, question 63

Question 63 of the NEET 2021 paper (code O1) is a Chemistry question from Hydrocarbons. Its idea, Nomenclature of Alkenes, was asked only this once in NEET 2017–2026. The NTA final answer key gives option 3.

Updated 2026-10-08

Q63 · Chemistry

The correct structure of 2,6-Dimethyl-dec-4-ene is :

The figure, described in words

Four skeletal (bond-line) structures as options; each is a C10 chain with an isopropyl end and methyl branches, differing in double-bond and methyl positions.

  1. 1[skeletal structure: (CH3)2CH−CH=CH−CH2−CH(CH3)−CH2CH2CH2CH3\mathrm{(CH_3)_2CH-CH=CH-CH_2-CH(CH_3)-CH_2CH_2CH_2CH_3} (trans double bond)]
  2. 2[skeletal structure: (CH3)2CH−CH2−CH2−CH=C(CH3)−CH2CH2CH2CH3\mathrm{(CH_3)_2CH-CH_2-CH_2-CH=C(CH_3)-CH_2CH_2CH_2CH_3}]
  3. 3[skeletal structure: (CH3)2CH−CH2−CH=CH−CH(CH3)−CH2CH2CH2CH3\mathrm{(CH_3)_2CH-CH_2-CH=CH-CH(CH_3)-CH_2CH_2CH_2CH_3} (cis double bond)]Official answer
  4. 4[skeletal structure: (CH3)2CH−CH2−CH(CH3)−CH2−CH=CH−CH2CH3\mathrm{(CH_3)_2CH-CH_2-CH(CH_3)-CH_2-CH=CH-CH_2CH_3} (trans double bond)]

Official answer: option 3 · NTA final answer key

Same idea

The only question on Nomenclature of Alkenes

No other NEET paper from 2017–2026 tested this exact idea.

Nomenclature of Alkenes: every question and how it was framed

The chapter

Hydrocarbons in ten years of NEET

25 questions from 2017–2026, asked in 10 of 10 papers, about 2.4 a paper. Hydrocarbons (Alkenes) alone had 12.

Chapter analysisStudy this chapterPractise this chapter

Hydrocarbons: questions per paper

0363’171’182’192’204’212’222’231’245’253’26