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Saturday, 31 October

JEE Main 2024 · ChemistryMultiple choiceDiagram basedMediumConceptual

JEE Main 8 April 2024, Shift 1, Chemistry Q80

Question 80 of 90 in this shift, Chemistry question 20 of 30, Section A.

The incorrect statement regarding the given structure is [figure: Fischer projection: CHO at top; then H-C-OH, HO-C-H, H-C-OH, H-C-OH; CH2_2OH at bottom]

The figure, in words

Fischer projection of an aldohexose: CHO top; C2 H left/OH right; C3 HO left/H right; C4 H left/OH right; C5 H left/OH right; CH2OH bottom.
  1. (1)has 4 asymmetric carbon atom
  2. (2)can be oxidized to a dicarboxylic acid with Br2\mathrm{Br_2} waterOfficial answer
  3. (3)despite the presence of −-CHO does not give Schiff's test
  4. (4)will coexist in equilibrium with 2 other cyclic structure

Official answer

Option 2

NTA final key.

Chapter
Biomolecules
Topic
Carbohydrates
Idea tested
Selective Oxidation of Monosaccharides

Same idea in other shifts

Asked 4× in all
  1. 4 Apr 2026, Shift 2 · Q68A D-aldotetrose on oxidation with concentrated HNO3\mathrm{HNO_3} resulted in optically inactive dicarboxylic acid. The structure of the…MediumDiagram basedHas a figure
  2. 31 Jan 2024, Shift 1 · Q79Match List I with List II LIST I A. Glucose/NaHCO3\mathrm{NaHCO_3}/Δ\Delta B. Glucose/HNO3\mathrm{HNO_3} C. Glucose/HI/Δ\Delta D.…MediumMatch the list
  3. 27 Jun 2022, Shift 1 · Q79L-isomer of a compound ‘A’ (C4H8O4\mathrm{C_4H_8O_4}) gives a positive test with [Ag(NH3)2]+\mathrm{[Ag(NH_3)_2]^+}. Treatment of ‘A’ with acetic…HardDiagram 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.