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Friday, 9 October

NEET UG 2021 · Chemistry · Question 89

NEET 2021 Chemistry, question 89

Question 89 of the NEET 2021 paper (code O1) is a Chemistry question from Aldehydes, Ketones and Carboxylic Acids. Its idea, Chemoselective Hydride Reduction, was asked only this once in NEET 2017–2026. The NTA final answer key gives option 2.

Updated 2026-10-08

Q89 · Chemistry

The product formed in the following chemical reaction is :

[cyclohexanone with −CH2−CO−OCH3\mathrm{-CH_2-CO-OCH_3} at C-2 and −CH3\mathrm{-CH_3} at C-3] →C2H5OHNaBH4\mathrm{\xrightarrow[C_2H_5OH]{NaBH_4}} ?

The figure, described in words

Reactant drawn as cyclohexanone ring bearing CH2–CO–OCH3 at C2 and CH3 at C3; options drawn as ring structures.

  1. 1[cyclohexanol (ring C=O reduced to CH–OH) with −CH2−CH(OH)−CH3\mathrm{-CH_2-CH(OH)-CH_3} at C-2 and −CH3\mathrm{-CH_3} at C-3]
  2. 2[cyclohexanol (ring C=O reduced to CH–OH) with −CH2−CO−OCH3\mathrm{-CH_2-CO-OCH_3} at C-2 and −CH3\mathrm{-CH_3} at C-3]Official answer
  3. 3[cyclohexanol (ring C=O reduced to CH–OH) with −CH2−CH(OH)−OCH3\mathrm{-CH_2-CH(OH)-OCH_3} at C-2 and −CH3\mathrm{-CH_3} at C-3]
  4. 4[cyclohexanone (ring C=O retained) with −CH2−CH2−OH\mathrm{-CH_2-CH_2-OH} at C-2 and −CH3\mathrm{-CH_3} at C-3]

Official answer: option 2 · NTA final answer key

Same idea

The only question on Chemoselective Hydride Reduction

No other NEET paper from 2017–2026 tested this exact idea.

Chemoselective Hydride Reduction: every question and how it was framed

The chapter

Aldehydes, Ketones and Carboxylic Acids in ten years of NEET

27 questions from 2017–2026, asked in 10 of 10 papers, about 2.6 a paper. Aldehydes, Ketones and Carboxylic Acids alone had 22.

Chapter analysisStudy this chapterPractise this chapter

Aldehydes, Ketones and Carboxylic Acids: questions per paper

0242’171’181’192’204’214’223’234’243’253’26