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Friday, 9 October

JEE Main 2025 · ChemistryMultiple choiceSingle correctMediumApplication

JEE Main 8 April 2025, Shift 2, Chemistry Q67

Question 67 of 75 in this shift, Chemistry question 17 of 25, Section A.

Which one of the following reactions will not lead to the desired ether formation in major proportion ? (iso-Bu ⇒ isobutyl, sec-Bu ⇒ sec-butyl, nPr ⇒ n−propyl, t^tBu ⇒ tert−butyl, Et ⇒ ethyl)

The figure, in words

Each option is a Williamson ether synthesis drawn with a cyclohexane ring (option 1) or a benzene ring (option 3) as the aryl/alkyl group.
  1. (1)[cyclohexyl]-O−^-Na+^+ + CH3Br\mathrm{CH_3Br} → [cyclohexyl]-O−CH3\mathrm{CH_3}
  2. (2)iso-BuO−^-Na+^+ + sec−BuBr → sec−Bu−O−iso−BuOfficial answer
  3. (3)Na+^+ −^-O−[phenyl] + n−PrBr → n−Pr−O−[phenyl]
  4. (4)t^tBuO−^-Na+^+ + EtBr → t^tBu−O−Et

Official answer

Option 2

NTA final key.

Chapter
Alcohols, Phenols and Ethers
Topic
Ethers
Idea tested
Williamson Synthesis Limits

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. 29 Jan 2024, Shift 1 · Q77The major product (P) in the following reaction isMediumDiagram basedHas a figure
  4. 2 Sep 2020, Shift 1 · Q43The major aromatic product C in the following reaction sequence will be : 2-methyl-2H-chromene (benzene ring fused to a pyran ring with O,…HardDiagram 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 42 of the 174 JEE Main shifts held from 2017 to 2026.