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Friday, 9 October

JEE Main 2025 · ChemistryMultiple choiceSingle correctMediumMulti-step

JEE Main 4 April 2025, Shift 2, Chemistry Q70

Question 70 of 75 in this shift, Chemistry question 20 of 25, Section A.

A dipeptide, "x" on complete hydrolysis gives "y" and "z". "y" on treatment with aq. HNO2\mathrm{HNO_2} produces lactic acid. On the other hand "z" on heating gives the following cyclic molecule. [figure: six-membered ring with two C=O and two N-H (2,5-diketopiperazine): C(=O)−NH−CH2−C(=O)−NH−CH2\mathrm{C(=O)-NH-CH_2-C(=O)-NH-CH_2} ring] Based on the information given, the dipeptide X is :

The figure, in words

Cyclic diamide (diketopiperazine): ring of C(=O), N-H, CH2, C(=O), N-H, CH2.
  1. (1)alanine-glycineOfficial answer
  2. (2)alanine-alanine
  3. (3)valine-glycine
  4. (4)valine-leucine

Official answer

Option 1

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 42 of the 174 JEE Main shifts held from 2017 to 2026.