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Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctMediumConceptual

JEE Main 3 September 2020, Shift 2, Chemistry Q26

Question 26 of 75 in this shift, Chemistry question 1 of 25.

An ionic micelle is formed on the addition of :

The figure, in words

Options 2 and 4 contain drawn structures. Both show a five-membered ring with two N atoms, a double bond drawn at the top of the ring and a C=N double bond; the left N carries H3C and the right N carries CH3 and a circled plus. Option 2: PF6 with a circled minus beside the cation. Option 4: a zigzag chain drawn to the right of the cation, ending in SO4 with a minus sign.
  1. (1)liquid diethyl ether to aqueous NaCl\mathrm{NaCl} solution
  2. (2)excess water to liquid [figure: five-membered ring cation with two N atoms, one N carrying a circled plus, H3C\mathrm{H_3C} on one N and CH3\mathrm{CH_3} on the other, with PF6⊖\mathrm{PF_6^{\ominus}} beside it]
  3. (3)sodium stearate to pure toluene
  4. (4)excess water to liquid [figure: same five-membered ring cation (H3C\mathrm{H_3C} and CH3\mathrm{CH_3} on the two N atoms, circled plus on one N) with a separate zigzag chain beside it ending in SO4−\mathrm{SO_4^-}]Official answer

Official answer

Option 4

NTA final key (Sep 2020).

Chapter
Surface Chemistry
Topic
Colloids
Idea tested
Micelle Formation and CMC

Same idea in other shifts

Asked 5× in all
  1. 25 Jul 2022, Shift 2 · Q65For micelle formation, which of the following statements are correct ? A. Micelle formation is an exothermic process. B. Micelle formation…MediumOther
  2. 25 Jun 2022, Shift 1 · Q79Using very little soap while washing clothes, does not serve the purpose of cleaning of clothes, because :EasySingle correct
  3. 25 Jul 2021, Shift 1 · Q32Sodium 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…MediumSingle correct
  4. 5 Sep 2020, Shift 1 · Q45Identify the correct molecular picture showing what happens at the critical micellar concentration (CMC) of an aqueous solution of a…EasyDiagram basedHas 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 108 of the 174 JEE Main shifts held from 2017 to 2026.