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Friday, 9 October

JEE Main 2020 · ChemistryMultiple choiceDiagram basedMediumApplication

JEE Main 2 September 2020, Shift 1, Chemistry Q44

Question 44 of 75 in this shift, Chemistry question 19 of 25.

Which of the following compounds will show retention in configuration on nucleophilic substitution by OH−\mathrm{OH^-} ion ?

The figure, in words

Options are condensed structural formulas drawn with the substituent below the central carbon (written out in the option text).
  1. (1)CH3−CH(Br)−C6H5\mathrm{CH_3-CH(Br)-C_6H_5} (the C6H5\mathrm{C_6H_5} drawn below the CH)
  2. (2)CH3−C(Br)(H)−C6H13\mathrm{CH_3-C(Br)(H)-C_6H_{13}} (Br above, H to the right, C6H13\mathrm{C_6H_{13}} below the central carbon)
  3. (3)CH3−CH(C2H5)−CH2Br\mathrm{CH_3-CH(C_2H_5)-CH_2Br} (the C2H5\mathrm{C_2H_5} drawn below the CH)Official answer
  4. (4)CH3−CH(Br)−CH3\mathrm{CH_3-CH(Br)-CH_3} (the second CH3\mathrm{CH_3} drawn below the CH)

Official answer

Option 3

NTA final key (Sep 2020).

Chapter
Haloalkanes and Haloarenes
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

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.