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Friday, 9 October

JEE Main 2025 · ChemistryMultiple choiceSingle correctMediumMulti-step

JEE Main 2 April 2025, Shift 1, Chemistry Q66

Question 66 of 75 in this shift, Chemistry question 16 of 25, Section A.

An optically active alkyl halide C4H9Br\mathrm{C_4H_9Br} [A] reacts with hot KOH dissolved in ethanol and forms alkene [B] as major product which reacts with bromine to give dibromide [C]. The compound [C] is converted into a gas [D] upon reacting with alcoholic NaNH2\mathrm{NaNH_2}. During hydration 18 gram of water is added to 1 mole of gas [D] on warming with mercuric sulphate and dilute acid at 333 K to form compound [E]. The IUPAC name of compound [E] is :
  1. (1)Butan-2-oneOfficial answer
  2. (2)Butan-1-al
  3. (3)But-2-yne
  4. (4)Butan-2-ol

Official answer

Option 1

NTA final key.

Chapter
Haloalkanes and Haloarenes
Topic
Alkenes and Alkynes
Idea tested
Kucherov Alkyne Hydration

Same idea in other shifts

Asked 2× in all
  1. 6 Apr 2026, Shift 2 · Q65An optically active alkyl bromide C4H9Br\mathrm{C_4H_9Br}, reacts with ethanolic KOH to form major compound [A] which reacts with bromine to…MediumSingle correct

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. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.