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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceDiagram basedHardMulti-step

JEE Main 26 February 2021, Shift 2, Chemistry Q45

Question 45 of 90 in this shift, Chemistry question 15 of 30, Section A.

Identify A in the following chemical reaction. [structure drawn: benzene ring with CHO at one position and CH3O\mathrm{CH_3O} at the opposite (para) position] →i) HCHO, NaOH; ii) CH3CH2Br, NaH, DMF; iii) HI, Δ\xrightarrow{\text{i) HCHO, NaOH; ii) }\mathrm{CH_3CH_2Br}\text{, NaH, DMF; iii) HI, }\Delta} A

The figure, in words

Reactant: benzene ring with CHO at the upper right and CH3O at the lower left (para). Reagents stacked on the arrow: i) HCHO, NaOH; ii) CH3CH2Br, NaH, DMF; iii) HI, delta.
  1. (1)[structure: benzene ring with HO at one position and C(=O)−OCH2CH3\mathrm{C(=O)-OCH_2CH_3} (C with =O, bonded to OCH2CH3\mathrm{OCH_2CH_3}) at the opposite position]
  2. (2)[structure: benzene ring with HO and CH2I\mathrm{CH_2I} at opposite positions]Official answer
  3. (3)[structure: benzene ring with HO and CH2OH\mathrm{CH_2OH} at opposite positions]
  4. (4)[structure: benzene ring with CH3O\mathrm{CH_3O} and CH2OH\mathrm{CH_2OH} at opposite positions]

Official answer

Option 2

NTA final key.

Chapter
Aldehydes, Ketones and Carboxylic Acids
Topic
Aldol and Cannizzaro
Idea tested
Cross-Cannizzaro Reaction

Same topic in other shifts

All Aldol and Cannizzaro questions
  1. 2 Apr 2026, Shift 2 · Q66An organic compound 'x' where molar ratio of C, O and H are equal, on treatment with 50% KOH under reflux followed by acidification…MediumSingle correct
  2. 6 Apr 2026, Shift 2 · Q64'xx' is the product which is obtained by the hydrolysis of prop-1-yne in the presence of mercuric sulphate under dilute acidic medium at…MediumSingle correct
  3. 2 Apr 2025, Shift 1 · Q68Given below are two statements : Statement (I) : Vanillin ([structure: benzene ring with -CHO, -OH para to CHO and -OCH3 ortho to OH])…MediumTwo statementsHas a figure
  4. 3 Apr 2025, Shift 2 · Q68The major product (P) in the following reaction is : Ph−CO−CHO\mathrm{Ph{-}CO{-}CHO} →ΔKOH\xrightarrow[\Delta]{\mathrm{KOH}} P (Major Product)MediumDiagram basedHas a figure
  5. 8 Apr 2025, Shift 2 · Q68When [structure: CH3C(=O)CH2CH2CH2CH2CHO\mathrm{CH_3C(=O)CH_2CH_2CH_2CH_2CHO}, a skeletal zigzag chain with a methyl ketone at one end and an aldehyde (C=O…MediumSingle correctHas a figure
  6. 4 Apr 2024, Shift 1 · Q78Given below are two statements : Statements I : Acidity of α\alpha-hydrogens of aldehydes and ketones is responsible for Aldol reaction.…MediumTwo statements

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.