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Chemistry - Liquid Solution Question with Solution | TestHub

ChemistryLiquid SolutionRaoult's LawMedium2 minQB

ChemistryMediumnumerical

Passage / Comprehension

An ideal binary solution of A and B has a vapour pressure of 900 torr. It is distilled at constant temperature till $\frac{2}{3}$ of the original amount is distilled. If the mole fraction of 'A' in the residue and the mole fraction of 'B' in the condensate are 0.3 and 0.4, respectively and the vapour pressure of residue is 860 torr, then (1 bar = 750 torr) :

Vapour pressure of pure ' A ' in torr is equal to :

Answer:

1000.00

Solution:

$900 = P^{\circ}_{A} \times 0.5 + P^{\circ}_{B} \times 0.5$ .......(1)

$860 = P^{\circ}_{A} \times 0.3 + P^{\circ}_{B} \times 0.7$

or, $\frac{860 \times 0.5}{0.7} = \frac{P _{A}^{O} \times 0.3 \times 0.5}{0.7} + P_{B}^{O} \times 0.5$ .......(2)

(1) - (2) $\Rightarrow 900 - \frac{860 \times 5}{7} = 0.5 P_{A}^{\circ} (1 - \frac{0.3}{0.7})$

or, $\frac{6300 - 4300}{7} = \frac{0.5 P _{A}^{0} \times 4}{7}$

or, $2000 = 2 P^{\circ}_{A} \Rightarrow P_{A}^{\circ} = 1000$ torr

Stream:JEESubject:ChemistryTopic:Liquid SolutionSubtopic:Raoult's Law

⏱ 2mℹ️ Source: QB

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