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Saturday, 31 October

JEE Main 2021 · ChemistryNumerical answerNumerical valueMediumCalculation

JEE Main 27 August 2021, Shift 2, Chemistry Q52

Question 52 of 90 in this shift, Chemistry question 22 of 30, Section B.

Two flasks I and II shown below are connected by a valve of negligible volume. [figure: two circular flasks joined through a valve; flask I contains 2.8 g N2\mathrm{N_2}, 300 K, 1 L; flask II contains 0.2 g N2\mathrm{N_2}, 60 K, 2 L] When the valve is opened, the final pressure of the system in bar is x×10−2x \times 10^{-2}. The value of xx is __________. (Integer answer) [Assume - Ideal gas; 1 bar = 10510^5 Pa; Molar mass of N2\mathrm{N_2} = 28.0 g mol−1\mathrm{mol^{-1}}; R = 8.31 J mol−1\mathrm{mol^{-1}} K−1\mathrm{K^{-1}}]

The figure, in words

Two circular flasks I (left) and II (right) joined by a valve. Flask I: 2.8 g N2, 300 K, 1 L. Flask II: 0.2 g N2, 60 K, 2 L.

Official answer

84

NTA final key.

Chapter
States of Matter
Topic
Ideal Gas Laws
Idea tested
Connected Gas Bulbs Equilibrium

Same idea in other shifts

Asked 4× in all
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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.