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Friday, 9 October

JEE Main 2021 · ChemistryMultiple choiceSingle correctMediumConceptual

JEE Main 25 July 2021, Shift 1, Chemistry Q32

Question 32 of 90 in this shift, Chemistry question 2 of 30, Section A.

Sodium stearate CH3(CH2)16COO−Na+\mathrm{CH_3(CH_2)_{16}COO^-Na^+} is an anionic surfactant which forms micelles in oil. Choose the correct statement for it from the following :
  1. (1)It forms spherical micelles with CH3(CH2)16−\mathrm{CH_3(CH_2)_{16}-} group pointing outwards on the surface of sphere.
  2. (2)It forms non-spherical micelles with −COO⊖\mathrm{-COO^{\ominus}} group pointing outwards on the surface.
  3. (3)It forms spherical micelles with CH3(CH2)16−\mathrm{CH_3(CH_2)_{16}-} group pointing towards the centre of sphere.Official answer
  4. (4)It forms non-spherical micelles with CH3(CH2)16−\mathrm{CH_3(CH_2)_{16}-} group pointing towards the centre.

Official answer

Option 3

NTA final key.

Chapter
Surface Chemistry
Topic
Colloids
Idea tested
Micelle Formation and CMC

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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. Lumi analyses 42 of the 174 JEE Main shifts held from 2017 to 2026.