Learn

Saturday, 31 October

JEE Main 2020 · ChemistryMultiple choiceSingle correctMediumMulti-step

JEE Main 2 September 2020, Shift 2, Chemistry Q45

Question 45 of 75 in this shift, Chemistry question 20 of 25.

Two compounds A and B with same molecular formula (C3H6O\mathrm{C_3H_6O}) undergo Grignard’s reaction with methylmagnesium bromide to give products C and D. Products C and D show following chemical tests. Test | C | D Ceric ammonium nitrate Test | Positive | Positive Lucas Test | Turbidity obtained after five minutes | Turbidity obtained immediately Iodoform Test | Positive | Negative C and D respectively are :

The figure, in words

Table printed in the stem (Test / C / D, three rows). Options are drawn condensed structural formulas with the OH or CH3 groups drawn above/below the chain carbon as stated in each option.
  1. (1)C =H3C−CH2−CH2−CH2−OH= \mathrm{H_3C-CH_2-CH_2-CH_2-OH}; D =H3C−CH2−CH−CH3= \mathrm{H_3C-CH_2-CH-CH_3} with OH drawn below the CH
  2. (2)C =H3C−CH2−CH2−CH2−OH= \mathrm{H_3C-CH_2-CH_2-CH_2-OH}; D =H3C−C−OH= \mathrm{H_3C-C-OH} with CH3\mathrm{CH_3} drawn above and CH3\mathrm{CH_3} drawn below the C
  3. (3)C =H3C−CH2−CH−CH3= \mathrm{H_3C-CH_2-CH-CH_3} with OH drawn above the CH; D =H3C−C−OH= \mathrm{H_3C-C-OH} with CH3\mathrm{CH_3} drawn above and CH3\mathrm{CH_3} drawn below the COfficial answer
  4. (4)C =H3C−C−OH= \mathrm{H_3C-C-OH} with CH3\mathrm{CH_3} drawn above and CH3\mathrm{CH_3} drawn below the C; D =H3C−CH2−CH−CH3= \mathrm{H_3C-CH_2-CH-CH_3} with OH drawn below the CH

Official answer

Option 3

NTA final key (Sep 2020).

Chapter
Alcohols, Phenols and Ethers
Topic
Alcohols and Phenols
Idea tested
Lucas Test Differentiation

Same idea in other shifts

Asked 3× in all
  1. 4 Apr 2026, Shift 2 · Q70Match the LIST-I with LIST-II List-I (Compound): A. [figure: cyclohexane ring bearing OH] B. [figure: cyclohexane ring bearing NH2] C.…MediumMatch the listHas a figure
  2. 4 Sep 2020, Shift 1 · Q39An organic compound (A) (molecular formula C6H12O2\mathrm{C_6H_{12}O_2}) was hydrolysed with dil. H2SO4\mathrm{H_2SO_4} to give a carboxylic acid…MediumDiagram 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.