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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctHardMulti-step

JEE Main 2 September 2020, Shift 2, Chemistry Q43

Question 43 of 75 in this shift, Chemistry question 18 of 25.

An organic compound ‘A’ (C9H10O\mathrm{C_9H_{10}O}) when treated with conc. HI undergoes cleavage to yield compounds ‘B’ and ‘C’. ‘B’ gives yellow precipitate with AgNO3\mathrm{AgNO_3} where as ‘C’ tautomerizes to ‘D’. ‘D’ gives positive iodoform test. ‘A’ could be :

The figure, in words

All four options are drawn structures: a six-membered ring (alternating double bonds drawn) with the printed side-chain text as given in the option text.
  1. (1)[figure: benzene ring (six-membered ring with alternating double bonds drawn) bonded to −O−CH2−CH=CH2-\mathrm{O}-\mathrm{CH_2}-\mathrm{CH}=\mathrm{CH_2} (printed)]
  2. (2)[figure: benzene ring (six-membered ring with alternating double bonds drawn) bonded to −CH2−O−CH=CH2-\mathrm{CH_2}-\mathrm{O}-\mathrm{CH}=\mathrm{CH_2} (printed)]Official answer
  3. (3)[figure: benzene ring (six-membered ring with alternating double bonds drawn) bonded to −O−CH=CH−CH3-\mathrm{O}-\mathrm{CH}=\mathrm{CH}-\mathrm{CH_3} (printed)]
  4. (4)[figure: benzene ring (six-membered ring with alternating double bonds drawn) with H3C on its left and −O−CH=CH2-\mathrm{O}-\mathrm{CH}=\mathrm{CH_2} (printed) on its right, at opposite ends of the ring]

Official answer

Option 2

NTA final key (Sep 2020).

Chapter
Alcohols, Phenols and Ethers
Topic
Ethers
Idea tested
Cleavage of Vinyl Ethers

Same topic in other shifts

All Ethers questions
  1. 6 Apr 2026, Shift 2 · Q66Consider the following reaction. [figure: benzyl phenyl ether, C6H5−O−CH2−C6H5\mathrm{C_6H_5{-}O{-}CH_2{-}C_6H_5}] ++ HI →\rightarrow Product…EasyTwo statementsHas a figure
  2. 4 Apr 2025, Shift 2 · Q68A toxic compound "A" when reacted with NaCN in aqueous acidic medium yields an edible cooking component and food preservative "B". "B" is…HardSingle correct
  3. 8 Apr 2025, Shift 2 · Q67Which one of the following reactions will not lead to the desired ether formation in major proportion ? (iso-Bu ⇒ isobutyl, sec-Bu ⇒…MediumSingle correctHas a figure
  4. 29 Jan 2024, Shift 1 · Q77The major product (P) in the following reaction isMediumDiagram basedHas a figure
  5. 10 Apr 2023, Shift 1 · Q75Suitable reaction condition for preparation of Methyl phenyl ether isEasySingle correct
  6. 28 Jul 2022, Shift 2 · Q44Compound I is heated with Conc. HI to give a hydroxy compound A which is further heated with Zn dust to give compound B. Identify A and B.…EasyDiagram 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.