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Friday, 9 October

JEE Main 2025 · ChemistryNumerical answerNumerical valueMediumMulti-step

JEE Main 7 April 2025, Shift 2, Chemistry Q75

Question 75 of 75 in this shift, Chemistry question 25 of 25, Section B.

Identify the structure of the final product (D) in the following sequence of the reactions : Ph−C(=O)−CH3→ΔPCl5A→3 eq. NaNH2/NH3B→AcidifyC→2. H2O2/OH−1. B2H6D\mathrm{Ph-C(=O)-CH_3}\xrightarrow[\Delta]{PCl_5}A\xrightarrow{3\ eq.\ NaNH_2/NH_3}B\xrightarrow{Acidify}C\xrightarrow[2.\ H_2O_2/OH^-]{1.\ B_2H_6}D Total number of sp2sp^2 hybridised carbon atoms in product D is __________.

The figure, in words

Reaction scheme: acetophenone (Ph-CO-CH3) treated with PCl5 (heat) gives A; A with 3 eq. NaNH2/NH3 gives B; acidify gives C; then 1. B2H6, 2. H2O2/OH- gives D.

Official answer

7

NTA final key.

Chapter
Haloalkanes and Haloarenes
Topic
Alkenes and Alkynes
Idea tested
Alkyne Hydroboration-Oxidation

Same topic in other shifts

All Alkenes and Alkynes questions
  1. 4 Apr 2026, Shift 1 · Q64An alkene (X) on ozonolysis followed by reduction gives following products. H−CHO\mathrm{H-CHO} (2 moles), OHC−CO−CHO\mathrm{OHC-CO-CHO}…HardDiagram basedHas a figure
  2. 4 Apr 2026, Shift 2 · Q64Compound (X) is subjected to the sequence of reactions as shown above. Molar mass of the major product (Y) formed is ________…MediumDiagram basedHas a figure
  3. 5 Apr 2026, Shift 1 · Q64"P" is a hydrocarbon of molecular formula:- C8H14\mathrm{C_8H_{14}}. On ozonolysis, "P" forms "Q". "Q" on treatment with alkali under reflux…HardDiagram basedHas a figure
  4. 6 Apr 2026, Shift 1 · Q66Given below are two statements: Statement I: 3-phenylpropene reacts with HBr and gives secondary alkyl bromide having a chiral carbon atom…MediumTwo statements
  5. 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
  6. 2 Apr 2025, Shift 1 · Q66An optically active alkyl halide C4H9Br\mathrm{C_4H_9Br} [A] reacts with hot KOH dissolved in ethanol and forms alkene [B] as major product…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. 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.