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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceSingle correctEasyConceptual

JEE Main 6 April 2024, Shift 1, Chemistry Q79

Question 79 of 90 in this shift, Chemistry question 19 of 30, Section A.

Which among the following aldehydes is most reactive towards nucleophilic addition reactions?

The figure, in words

Options are drawn aldehydes with the C=O drawn vertically above the carbon: H-CO-H, CH3-CO-H, C2H5-CO-H, C3H7-CO-H.
  1. (1)H−C(=O)−H\mathrm{H-C(=O)-H}Official answer
  2. (2)CH3−C(=O)−H\mathrm{CH_3-C(=O)-H}
  3. (3)C2H5−C(=O)−H\mathrm{C_2H_5-C(=O)-H}
  4. (4)C3H7−C(=O)−H\mathrm{C_3H_7-C(=O)-H}

Official answer

Option 1

NTA final key.

Chapter
Aldehydes, Ketones and Carboxylic Acids
Topic
Nucleophilic Addition
Idea tested
Aldehyde vs Ketone Reactivity

Same idea in other shifts

Asked 3× in all
  1. 2 Sep 2020, Shift 1 · Q42The increasing order of the following compounds towards HCN addition is : (i) 3-methoxybenzaldehyde (H3CO\mathrm{H_3CO} meta to CHO) (ii)…MediumDiagram basedHas a figure
  2. 3 Sep 2020, Shift 2 · Q39The increasing order of the reactivity of the following compounds in nucleophilic addition reaction is : Propanal, Benzaldehyde,…MediumSingle correct

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.