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Saturday, 31 October

JEE Main · Chemistry · Aldehydes, Ketones and Carboxylic Acids

DIBAL-H Selective Reduction

JEE Main asked DIBAL-H Selective Reduction 4 times in 4 of the 108 shifts Lumi analysed, in 2017, 2021 and 2022. It belongs to Carboxylic Acids and Derivatives, in Aldehydes, Ketones and Carboxylic Acids (Chemistry). The longest wait between two years asking it was 4 years, across 2018 and 2019, which Lumi has no shifts for. In 2022 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
4
in 4 shifts
Years
3 of 8
First asked
2017
last in 2022
Pattern
Comes in cycles
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2017, 2021 and 2022. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Chemistry questions.

00.510.83’170’200.03’210.07’220’230’240’250’26

Raw count: 2017: 1 in 1 shift · 2020: 0 in 12 shifts · 2021: 1 in 24 shifts · 2022: 2 in 24 shifts · 2023: 0 in 12 shifts · 2024: 0 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20260 of 9
  • 20250 of 8
  • 20240 of 18
  • 20230 of 12
  • 20222 of 24
  • 20211 of 24
  • 20200 of 12
  • 20171 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Diagram based is the usual form. Skill tested: application.

  • Predict product of reaction
  • Identify incorrect reaction among preparations

Difficulty

Easy 0Medium 4Hard 0

Every question was multiple choice.

Every question

All 4 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 29 Jul 2022, Shift 1 · Q78Consider the following reaction sequence : [figure: 4-aminobenzonitrile (benzene ring with NH2\mathrm{NH_2} at top, CN at bottom)…MediumDiagram basedHas a figure
  2. 25 Jul 2022, Shift 1 · Q75Which one of the following reactions does not represent correct combination of substrate and product under the given conditions ?MediumDiagram basedHas a figure
  3. 25 Feb 2021, Shift 1 · Q46Which one of the following reactions will not form acetaldehyde ?MediumSingle correct
  4. 2 Apr 2017 (offline) · Q60The major product obtained in the following reaction is : [reaction: bicyclic lactone (cyclopentene fused to a five-membered lactone, with…MediumSingle correctHas a figure

Shifts: 2 Apr 2017 (offline), 25 Feb 2021, Shift 1, 25 Jul 2022, Shift 1, 29 Jul 2022, Shift 1.

Same topic

Other ideas in Carboxylic Acids and Derivatives

Carboxylic Acids and Derivatives has 15 ideas JEE Main has asked; 11 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas