JEE Main 2021ChemistrySolutionsMediumNumerical

JEE Main 2021 — Solutions Question with Solution

JEE Main 2021 (20 Jul Shift 1)

Question

At 20°C, the vapour pressure of benzene is 70 torr and that of methyl benzene is 20 torr. The mole fraction of benzene in the vapour phase at 20°C above an equimolar mixture of benzene and methyl benzene is __×10-2. (Nearest integer)

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Show full solutionCorrect answer: 78
Correct answer
78

Step-by-step explanation

PB∘=70PT∘=20XB=0.5=XT

Now yB=XBPB∘XBPBo+XTPT∘

=70×0.570×0.5+20×0.5=78×10-2

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About this question

This is a previous-year question from JEE Main 2021, covering the Solutions 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.