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Saturday, 31 October

JEE Main 2021 · ChemistryMultiple choiceDiagram basedMediumDiagram reading

JEE Main 3 August 2021, Shift 1, Chemistry Q48

Question 48 of 90 in this shift, Chemistry question 18 of 30, Section A.

The correct structure of β-D-deoxyribose present in DNA is

The figure, in words

Five-membered ring drawn in Haworth-type perspective with O at the top, the front bond drawn bold, and a HO– group on a vertical line at the upper left; each option differs in which positions carry H or OH.
  1. (1)[figure: five-membered ring drawn with O at top; HO– chain on the left ring carbon; the right ring carbon has H above and OH below; lower ring carbons: left carbon with OH below, right carbon with H below; H labels on the upper side of both lower carbons; H at the lower left of the left ring carbon]
  2. (2)[figure: five-membered ring as in the previous option; right ring carbon has OH above and H below; the lower right ring carbon has OH below; the lower left ring carbon has OH below]
  3. (3)[figure: five-membered ring as in the previous options; right ring carbon has OH above and H below; the lower right ring carbon has H below; the lower left ring carbon has OH below]Official answer
  4. (4)[figure: five-membered ring as in the previous options; right ring carbon has OH above and H below; the lower left ring carbon has H below; the lower right ring carbon has OH below]

Official answer

Option 3

NTA final key.

Chapter
Biomolecules
Topic
No close match in our taxonomy
Idea tested
No close match in our taxonomy

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.