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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedHardConceptual

JEE Main 9 January 2020, Shift 1, Chemistry Q44

Question 44 of 75 in this shift, Chemistry question 19 of 25, Section A.

The correct order of heat of combustion for following alkadienes is : (a) [drawn structure] (b) [drawn structure] (c) [drawn structure]

The figure, in words

Three drawn zigzag line structures labelled (a), (b), (c), each with two doubled (double-bond) horizontal segments. (a): from a short line at lower left, a double horizontal segment, then a line rising to the right to a second, higher double horizontal segment, then a line rising to the right (staircase shape). (b): same start, then a line rising to a second double horizontal segment at a peak, then a line descending to the right. (c): a line rising to a double horizontal segment at the top, then a line descending to the right to a second, lower double horizontal segment, then a line rising to the right.
  1. (1)(c) < (b) < (a)
  2. (2)(b) < (c) < (a)
  3. (3)(a) < (c) < (b)
  4. (4)(a) < (b) < (c)Official answer

Official answer

Option 4

NTA final key (Jan 2020).

Chapter
Hydrocarbons
Topic
Resonance and Hyperconjugation
Idea tested
Heat of Hydrogenation

Same topic in other shifts

All Resonance and Hyperconjugation questions
  1. 2 Apr 2026, Shift 2 · Q63Given below are two statements: Statement I: In…MediumSingle correct
  2. 5 Apr 2026, Shift 2 · Q63IUPAC name of the some alkenes are given below. Find out the correct stability order. A. 2-Methylbut-2-ene B. ciscis-But-2-ene C. 2,…MediumSingle correct
  3. 6 Apr 2026, Shift 2 · Q63Shown below is the structure of methyl acetate with three different α\alpha, β\beta and γ\gamma carbon - oxygen bonds. The correct…MediumDiagram basedHas a figure
  4. 3 Apr 2025, Shift 2 · Q65Given below are two statements: Statement I : Hyperconjugation is not a permanent effect. Statement II : In general, greater the number of…EasyTwo statements
  5. 4 Apr 2024, Shift 1 · Q74Match List I with List II : List - I (Mechanism steps) List - II (Effect) (A) [structure: aniline, lone pair on NH2_2 donated into ring,…MediumMatch the listHas a figure
  6. 6 Apr 2024, Shift 2 · Q88Number of carbocations from the following that are not stabilized by hyperconjugation is ________.MediumNumerical valueHas 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.