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Friday, 9 October

JEE Main 2023 · ChemistryMultiple choiceDiagram basedHardMulti-step

JEE Main 11 April 2023, Shift 1, Chemistry Q79

Question 79 of 90 in this shift, Chemistry question 19 of 30, Section A.

L-isomer of tetrose X (C4H8O4\mathrm{C_4H_8O_4}) gives positive Schiff's test and has two chiral carbons. On acetylation, 'X' yields triacetate. 'X' also undergoes following reactions 'A' ←HNO3\xleftarrow{\mathrm{HNO_3}} 'X' →NaBH4\xrightarrow{\mathrm{NaBH_4}} 'B' (Chiral compound) 'X' is

The figure, in words

Four options: Fischer projections of tetroses and ring structures.
  1. (1)[figure: Fischer projection: CHO top; HO on left, H on right; HO on left, H on right; CH2OH bottom]
  2. (2)[figure: furanose-type ring with ring O at lower left; left substituents H, H; right substituents OH, OH, H; CH2OH at bottom]
  3. (3)[figure: Fischer projection: CHO top; H on left, OH on right; HO on left, H on right; CH2OH bottom]Official answer
  4. (4)[figure: furanose-type ring with ring O at lower left; left substituents H, HO; right substituents OH, H, H; CH2OH at bottom]

Official answer

Option 3

NTA final key.

Chapter
Biomolecules
Topic
Carbohydrates
Idea tested
D and L Configuration of Sugars

Same idea in other shifts

Asked 2× in all
  1. 3 Apr 2025, Shift 1 · Q70Which of the following is the correct structure of L−-Fructose?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 42 of the 174 JEE Main shifts held from 2017 to 2026.