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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedMediumConceptual

JEE Main 2 September 2020, Shift 1, Chemistry Q42

Question 42 of 75 in this shift, Chemistry question 17 of 25.

The increasing order of the following compounds towards HCN addition is : (i) 3-methoxybenzaldehyde (H3CO\mathrm{H_3CO} meta to CHO) (ii) 2-nitrobenzaldehyde (NO2\mathrm{NO_2} ortho to CHO) (iii) 2-methoxybenzaldehyde (OCH3\mathrm{OCH_3} ortho to CHO) (iv) 3-nitrobenzaldehyde (O2N\mathrm{O_2N} meta to CHO)

The figure, in words

Four substituted benzaldehydes drawn and labelled (i)-(iv): (i) H3CO and CHO meta; (ii) CHO with NO2 ortho; (iii) CHO with OCH3 ortho; (iv) O2N and CHO meta.
  1. (1)(iii) < (iv) < (i) < (ii)
  2. (2)(iii) < (i) < (iv) < (ii)Official answer
  3. (3)(i) < (iii) < (iv) < (ii)
  4. (4)(iii) < (iv) < (ii) < (i)

Official answer

Option 2

NTA final key (Sep 2020).

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. 6 Apr 2024, Shift 1 · Q79Which among the following aldehydes is most reactive towards nucleophilic addition reactions?EasySingle correctHas 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.