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Friday, 9 October

JEE Main 2025 · ChemistryMultiple choiceSingle correctMediumConceptual

JEE Main 2 April 2025, Shift 1, Chemistry Q53

Question 53 of 75 in this shift, Chemistry question 3 of 25, Section A.

Two vessels A and B are connected via stopcock. The vessel A is filled with a gas at a certain pressure. The entire assembly is immersed in water and is allowed to come to thermal equilibrium with water. After opening the stopcock the gas from vessel A expands into vessel B and no change in temperature is observed in the thermometer. Which of the following statement is true ?

The figure, in words

Water bath with a thermometer (left) and a stirrer (right); two vessels, B on the left and A on the right, connected by a stopcock, both immersed in the water.
  1. (1)dw≠0\mathrm{d}w\neq0
  2. (2)dq≠0\mathrm{d}q\neq0
  3. (3)dU≠0\mathrm{d}U\neq0
  4. (4)The pressure in the vessel B before opening the stopcock is zeroOfficial answer

Official answer

Option 4

NTA final key.

Chapter
Thermodynamics (Chemistry)
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.