A gaseous mixture of two substances A and B, under a total pressure of $0.8$ atm is in equilibrium with an ideal liquid solution. The mole fraction of substance A is $0.5$ in the vapour phase and $0.2$ in the liquid phase. The vapour pressure of pure liquid $\mathrm{A}$ is __________ atm. (Nearest integer)
Answer (integer)
2
Solution
Given that $X_{A}=0.2, Y_{A}=0.5, P_{T}=0.8 \mathrm{~atm}$
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We know that $P_{A}=Y_{A} \times P_{T}$
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$P_{A}=0.5 \times 0.8=0.4$
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Now $P_{A}=X_{A} \times P_{A}^{\circ} \Rightarrow P_{A}^{\circ}=\frac{0.4}{0.2}=2 \mathrm{~atm}$
About this question
Subject: Chemistry · Chapter: States of Matter · Topic: Gas Laws
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