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)
Answer (integer)
1
Solution
x<sub>A</sub> = 0.6<br><br>P<sub>T</sub> = x<sub>A</sub>P<sub>A</sub><sup>o</sup> + x<sub>B</sub>P<sub>B</sub><sup>o</sup><br><br>= 0.6 $\times$ 90 + 0.4 $\times$ 15<br><br>= 54 + 6 = 60<br><br>x<sub>A</sub>P<sub>A</sub><sup>o</sup> = y<sub>A</sub>P<sub>T</sub><br><br>0.6 $\times$ 90 = y<sub>A</sub>(60)<br><br>$\Rightarrow$ y<sub>A</sub> = 0.9<br><br>y<sub>B</sub> = 0.1 = 1 $\times$ 10<sup>$-$1</sup><br><br>$\therefore$ x = 1
About this question
Subject: Chemistry · Chapter: States of Matter · Topic: Gas Laws
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