Q. The vapour pressure of two liquids X and Y are 80 and 60 Torr respectively. The total vapour pressure of the ideal solution obtained by mixing 3 moles of X and 2 moles of Y would be
A) 68 Torr
B) 140 Torr
C) 48 Torr
D) 72 Torr
Explanation
(d)
Mole of X, $n_{x} = \ \frac{3}{3 + 2} = \frac{3}{5}$
Moles of Y, $n_{y} = \ \frac{2}{3 + 2} = \frac{2}{5}$
$P_{T} = P_{x}n_{x} + P_{y}n_{y}$
$= 80 \times \frac{3}{5} + 60 \times \frac{2}{5}$
$\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ = 48 + 24 = 72\ Torr\$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.