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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceDiagram basedMediumMulti-step

JEE Main 4 August 2021, Shift 2, Chemistry Q44

Question 44 of 90 in this shift, Chemistry question 14 of 30, Section A.

The major products A and B in the following reaction sequence are [reaction scheme: see figure_note] (Ph = - C6H5\mathrm{C_6H_5})

The figure, in words

Reactant drawn: six-membered ring with a C=O (O drawn above). Arrow labelled '(i) C6H5MgBr dry ether, (ii) H3O+ (with a circled plus)' to A; second arrow labelled 'H2SO4, H2O' from A to B. Options drawn as labelled A = ..., B = ... skeletal rings with OH/Ph/O labels as described in the options.
  1. (1)A = [six-membered ring with OH and Ph on one ring carbon], B = [six-membered ring with Ph on one ring carbon]
  2. (2)A = [six-membered ring with OH and Ph on one ring carbon], B = [six-membered ring with one C=C double bond, Ph on a carbon of the double bond]Official answer
  3. (3)A = [six-membered ring with =O on one ring carbon and Ph on the adjacent ring carbon], B = [six-membered ring with OH on one ring carbon, OH on the next ring carbon, and Ph on the ring carbon after that]
  4. (4)A = [six-membered ring with =O on one ring carbon and Ph on the adjacent ring carbon], B = [six-membered ring with a circle drawn inside, OH on one ring carbon and Ph on the adjacent ring carbon]

Official answer

Option 2

NTA final key.

Chapter
Alcohols, Phenols and Ethers
Topic
Nucleophilic Addition
Idea tested
Grignard Reagent Addition

Same idea in other shifts

Asked 7× in all
  1. 12 Apr 2023, Shift 1 · Q76In the following reaction [figure: CH3-C(=O)-CH2-CH(CH3)-Br, (i) Mg (ii) H2O\mathrm{H_2O} -> 'A' (Major Product)] A isHardSingle correctHas a figure
  2. 25 Jun 2022, Shift 2 · Q76In the given reaction 2A2\mathrm{A} →(iii) H2O / H+(i) 2 Mg, THF; (ii) Methyl benzoate\xrightarrow[\text{(iii) } \mathrm{H_2O\ /\ H^+}]{\text{(i) 2 Mg, THF; (ii) Methyl benzoate}} [drawn…MediumDiagram basedHas a figure
  3. 26 Jun 2022, Shift 1 · Q75[figure: drawn structure with the label MgBr at its upper end and the label MgBr at its lower end, the two joined by a bracket-shaped…HardOtherHas a figure
  4. 27 Aug 2021, Shift 2 · Q44Which one of the following is the major product of the given reaction ? [reaction drawn: a fused bicyclic compound - a benzene ring (drawn…HardDiagram basedHas a figure
  5. 25 Jul 2021, Shift 2 · Q50A reaction of benzonitrile with one equivalent CH3MgBr\mathrm{CH_3MgBr} followed by hydrolysis produces a yellow liquid "P". The compound "P"…MediumSingle correct
  6. 9 Jan 2020, Shift 1 · Q45Identify (A) in the following reaction sequence : (A) Gives Positive iodoform test…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 108 of the 174 JEE Main shifts held from 2017 to 2026.