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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedHardMulti-step

JEE Main 4 September 2020, Shift 2, Chemistry Q45

Question 45 of 75 in this shift, Chemistry question 20 of 25.

The major product [C] of the following reaction sequence will be : CH2=CH−CHO→(ii) SOCl2(i) NaBH4\mathrm{CH_2=CH-CHO} \xrightarrow[\text{(ii) } \mathrm{SOCl_2}]{\text{(i) } \mathrm{NaBH_4}} [A] →Anhy. AlCl3[ring: hexagon with a circle inside]\xrightarrow[\mathrm{Anhy.\ AlCl_3}]{[\text{ring: hexagon with a circle inside}]} [B] →DBr\xrightarrow{\mathrm{DBr}} [C]

The figure, in words

Stem: reaction scheme with a ring drawn (hexagon with circle inside) above the second arrow; Anhy. AlCl3 below it. Options are drawn line structures.
  1. (1)[figure: ring (hexagon with a circle inside) bonded to a chain of three vertices; the second vertex carries D (drawn downward), the third vertex is bonded to Br]
  2. (2)[figure: ring (hexagon with a circle inside) bonded to a chain of three vertices; the second vertex carries Br (drawn downward), the third vertex is bonded to D]
  3. (3)[figure: ring (hexagon with a circle inside) bonded to a first vertex carrying Br (drawn upward); chain continues through two more vertices, the last bonded to D]Official answer
  4. (4)[figure: ring (hexagon with a circle inside) bonded to a first vertex carrying Br (drawn upward); the second vertex carries D (drawn downward); the chain ends at a third unlabelled vertex]

Official answer

Option 3

NTA final key (Sep 2020).

Chapter
Aldehydes, Ketones and Carboxylic Acids
Topic
Aromatic Hydrocarbons
Idea tested
Friedel-Crafts Alkylation

Same idea in other shifts

Asked 7× in all
  1. 4 Apr 2026, Shift 2 · Q56Match the LIST-I with LIST-II List-I (Reaction): A. Williamson Synthesis B. Friedel Craft Reaction C. Bromination of vinyl benzene D.…EasyMatch the list
  2. 5 Apr 2026, Shift 1 · Q65For the following Friedel Craft's alkylation reaction, which of the statements are correct? [figure: benzene + n-propyl chloride…MediumOtherHas a figure
  3. 10 Apr 2023, Shift 2 · Q74The major product 'P' formed in the given reaction is:HardDiagram basedHas a figure
  4. 29 Jun 2022, Shift 2 · Q74[figure: six-membered ring drawn with alternating double bonds] + CH3CH2CH2Cl\mathrm{CH_3CH_2CH_2Cl} → 'A' Major Product (reagent over the arrow:…MediumDiagram basedHas a figure
  5. 25 Feb 2021, Shift 2 · Q42The major product of the following reaction is : [figure: benzene ring (circle inside hexagon), then an arrow with a skeletal reagent…MediumDiagram basedHas a figure
  6. 8 Jan 2020, Shift 2 · Q50In the following sequence of reactions the maximum number of atoms present in molecule 'C' in one plane is __________.…MediumNumerical value

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.