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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 4 September 2020, Shift 1, Chemistry Q44

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

When neopentyl alcohol is heated with an acid, it slowly converted into an 85 : 15 mixture of alkenes A and B, respectively. What are these alkenes ?

The figure, in words

Each option is a pair of line drawings with printed labels H3C, CH3, CH2; left drawing is A and right is B [labels A/B from the stem order, not printed on the drawings].
  1. (1)[figure: A (left): a vertex with H3C (up-left) and H3C (down-left) double bonded to a vertex bearing CH3; B (right): the same H3C/H3C vertex single-bonded to a vertex double bonded to CH2]
  2. (2)[figure: A (left): same as option 1 left; B (right): H3C on the left vertex, which has a double bond down to CH2 and a single bond to a vertex with a vertical line up to CH3]Official answer
  3. (3)[figure: A (left): H3C/H3C vertex single-bonded to a vertex double bonded to CH2; B (right): H3C vertex with a double bond to CH2 (below) and a bond to the right then up to CH3]
  4. (4)[figure: A (left): CH3 at a vertex with =CH2 below and a bond up to a vertex with a vertical line to CH3; B (right): CH3/CH3 vertex bonded to a vertex double bonded to CH2]

Official answer

Option 2

NTA final key (Sep 2020).

Chapter
Alcohols, Phenols and Ethers
Topic
Alcohols and Phenols
Idea tested
Alcohol Dehydration Ease

Same idea in other shifts

Asked 7× in all
  1. 5 Apr 2026, Shift 1 · Q67Consider compounds A, B and C with following structural formulae A = CH3−CH2−CH2−CH2−CH2−OH\mathrm{CH_3-CH_2-CH_2-CH_2-CH_2-OH} B =…EasyOtherHas a figure
  2. 8 Apr 2024, Shift 1 · Q78Identify the major products A and B respectively in the following set of reactions. [figure: 1-methylcyclohexan-1-ol (ring carbon bearing…MediumDiagram basedHas a figure
  3. 13 Apr 2023, Shift 1 · Q89For the given reaction CH3−C(CH3)(CH3)−CH(OH)−C(H)(CH3)−CH3→ΔH+\mathrm{CH_3-C(CH_3)(CH_3)-CH(OH)-C(H)(CH_3)-CH_3}\xrightarrow[\Delta]{H^+} (the carbon bearing OH is labelled…MediumNumerical valueHas a figure
  4. 29 Jul 2022, Shift 2 · Q76When enthanol is heated with conc. H2SO4\mathrm{H_2SO_4}, a gas is produced. The compound formed, when this gas is treated with cold dilute…EasySingle correct
  5. 4 Aug 2021, Shift 2 · Q41In the reaction given below, [reaction scheme: drawn structure → A + B, see figure_note] the products A and B formed areMediumDiagram basedHas a figure
  6. 31 Aug 2021, Shift 1 · Q46The major product formed in the following reaction is :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.