JEE Main 2021ChemistryStates of MatterEasyNumerical

JEE Main 2021 — States of Matter Question with Solution

JEE Main 2021 (17 Mar Shift 2)

Question

The number of chlorine atoms in 20 mL of chlorine gas at STP is _______ 1021. (Round off to the Nearest Integer). [Assume chlorine is an ideal gas at STP R=0.083 L bar mol-1K-1, NA=6.023×1023]

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Correct answer
1

Step-by-step explanation

PV=nRT

1.0×201000=N6.023×1023×0.083×273

∴ Number of Cl2 molecules, N=5.3×1020

Hence, Number of Cl -atoms =1.06×1021

≈1×1021

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About this question

This is a previous-year question from JEE Main 2021, covering the States of Matter chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.