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Friday, 9 October

JEE Main 2022 · ChemistryMultiple choiceSingle correctMediumApplication

JEE Main 28 July 2022, Shift 1, Chemistry Q73

Question 73 of 90 in this shift, Chemistry question 13 of 30, Section A.

Choose the correct option for the following reactions. (CH3)3C−CH=CH2\mathrm{(CH_3)_3C-CH=CH_2} (3,3-dimethylbut-1-ene, drawn as H3C−C(CH3)(CH3)−CH=CH2\mathrm{H_3C-C(CH_3)(CH_3)-CH=CH_2}) →Hg(OAc)2, H2O / NaBH4\xrightarrow{\mathrm{Hg(OAc)_2,\ H_2O\ /\ NaBH_4}} A and the same alkene →(BH3)2 / H2O2, OH⊖\xrightarrow{\mathrm{(BH_3)_2\ /\ H_2O_2,\ OH^{\ominus}}} B

The figure, in words

Alkene H3C-C(CH3)2-CH=CH2 with two reaction arrows: right Hg(OAc)2, H2O / NaBH4 giving A; left (BH3)2 / H2O2, OH- giving B.
  1. (1)'A' and 'B' are both Markovnikov addition products.
  2. (2)'A' is Markovnikov product and 'B' is anti-Markovnikov product.Official answer
  3. (3)'A' and 'B' are both anti-Markovnikov products.
  4. (4)'B' is Markovnikov and 'A' is anti-Markovnikov product.

Official answer

Option 2

NTA final key (2022 Session 2).

Chapter
Hydrocarbons
Topic
Alkenes and Alkynes
Idea tested
Oxymercuration-Demercuration

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.