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The vapour pressure of pure liquid A and...

The vapour pressure of pure liquid A and liquid B at 350 K are 440 mm and 720 mm of Hg. If total vapour [ressure of solution is 580 mm of Hg then the mole fraction of liquid A in vapour phase will be :-

A

0.31

B

0.38

C

0.62

D

0.76

Text Solution

Verified by Experts

The correct Answer is:
B
`P_(s)=X_(A)P_(A)^(@)+X_(B)P_(B)^(@)`
`P_(s)=X_(A)P_(A)^(@)+(1-X_(A))P_(B)^(@)`
`:.580=X_(A)xx440+(1-X_(A))720`
`140=280X_(2)"and"X_(A)=0.5`
`Y_(A)=(P_(A))/(P_(S))=(0.5xx440)/(580)=0.38`
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