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Friday, 9 October

JEE Main 2022 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 25 July 2022, Shift 1, Chemistry Q75

Question 75 of 90 in this shift, Chemistry question 15 of 30, Section A.

Which one of the following reactions does not represent correct combination of substrate and product under the given conditions ?

The figure, in words

Each option is a reaction scheme on a para-methyl benzene ring giving the aldehyde (CHO) product, with the stated reagents.
  1. (1)[figure: p-toluoyl chloride (4-methylbenzoyl chloride) with H2, Pd.BaSO4 gives 4-methylbenzaldehyde]
  2. (2)[figure: 4-methylbenzonitrile with (i) DIBAL-H (ii) H2O gives 4-methylbenzaldehyde]
  3. (3)[figure: ethyl 4-methylbenzoate with (i) AlH(iso Bu)2 (ii) H2O gives 4-methylbenzaldehyde]
  4. (4)[figure: 4-methylbenzyl alcohol with (i) Na2Cr2O7 (ii) H2SO4, H2O gives 4-methylbenzaldehyde]Official answer

Official answer

Option 4

NTA final key (2022 Session 2).

Chapter
Aldehydes, Ketones and Carboxylic Acids
Topic
Carboxylic Acids and Derivatives
Idea tested
DIBAL-H Selective Reduction

Same idea in other shifts

Asked 2× in all
  1. 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

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.