Verified Solution • 2025–26 Session moderate

QJEEM21Chd40c: JEE Main 2021 Chemistry - Class 12 JEEM21Chd40c Solution: The vapour pressures of A and B at 25 C are 90 mm Hg and 15 mm…

The vapour pressures of A and B at 25 ∘^\circ C are 90 mm Hg and 15 mm Hg respectively. If A and B are mixed such that the mole fraction of A in the mixture is 0.6, then the mole fraction of B in the vapour phase is x ×\times 10 −- 1. The value of x is ___________. (Nearest integer)

Step-by-Step Verified Solution

xA = 0.6

PT = xAPAo + xBPBo

= 0.6 ×\times 90 + 0.4 ×\times 15

= 54 + 6 = 60

xAPAo = yAPT

0.6 ×\times 90 = yA(60)

⇒\Rightarrow yA = 0.9

yB = 0.1 = 1 ×\times 10 −- 1

∴\therefore x = 1

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