Home
Class 12
CHEMISTRY
Vapour pressure of pure 'A' is 70 mm of ...

Vapour pressure of pure 'A' is 70 mm of Hg at `25^(@)C`. It forms an ideal solution with 'B' in which mole fraction of A is 0.8 . If the vapour pressure of the solution is 84 mm of Hg at `25^(@)C`, the vapour pressure of pure 'B' at `25^(@)C` is :

A

56 mm

B

70 mm

C

140 mm

D

28 mm

Text Solution

Verified by Experts

The correct Answer is:
C
`p_("total")=p_(A)+p_(B)`
`=p_(A)^(@)x_(A)+p_(B)^(@)x_(B)`
`p_(A)^(@)=70` mm Hg, `x_(A)=0.8`
`p_(B)^(@)=? " " x_(B)=1-x_(A)=0.2`
`p_("total")=84` mm Hg.
`:.84=(70xx0.8)+(p_(B)^(@)xx0.2)`
`84=56+0.2 p_(B)^(@)`
`0.2p_(B)^(@)=84-56=28`
or `p_(B)^(@)=(28)/(0.2)=140` mm Hg.
Promotional Banner

Topper's Solved these Questions

  • SOLUTIONS

    MODERN PUBLICATION|Exercise Multiple Choice Questions (Level-III) (Questions from AIEEE/JEE Examinations)|14 Videos

  • REDOX REACTIONS

    MODERN PUBLICATION|Exercise Recent Examination Questions|6 Videos

  • SOME BASIC CONCEPTS OF CHEMISTRY

    MODERN PUBLICATION|Exercise RECENT EXAMINATION QUESTION|15 Videos

Similar Questions

Explore conceptually related problems

The vapour pressure of acetone at 298 K is 40 mm of Hg . Its mole fraction in a solution with alcohol is 0.80 . What is its vapour pressure in solution if the mixture obey Raoult's law?

Calculate the vapour pressure of the solution. The molefraction of the solute is 0.25. The vapour pressure of the pure solvent is 0.8atm.

The vapour pressure of ethyl alcohol at 298K is 40mm of Hg. Its mole fraction in a solution with methyl alcohol is 0.80. what is its vapoure pressure in solution. If the mixture obeys Raoult's law.

Vapour pressure of chloroform and dichloroethane at 298K are 200 mm Hg and 415 mm Hg respectively. If the mole fraction of chloroform is 0.312. calculate vapour pressure of the solution.

A solution containing 30 g of a non-volatile solute in exactly 90 g of water has a vapour pressure of 21.85 mm of 25^(@)C . Further 18 g of water is then added to the solution, the new vapour pressure becomes 22.15 mm of Hg at 25 C . Calculate the (a) molecular mass of the solute and (b) vapour pressure of water at 25^(@)C .

At 27^(@)C .the vapour pressure of an ideal solution containing 1 mole of A and 1 mole and B is 500 mm of Hg . At the same temperature, if 2 mol of B is added to this solution the vapour pressure of solution increases by 50 mm of Hg . The vapour pressure of A and B in their pure states is respectively.

The vapour pressure of a pure liquid A is 40 mm Hg at 310 K . The vapour pressure of this liquid in a solution with liquid B is 32 mm Hg . The mole fraction of A in the solution, if it obeys Raoult's law, is:

Two liquids A and B form ideal solution. At 300 K , the vapour pressure of a solution containing 1 mol of A and 3 mol of B is 500 mm of Hg. At the same temperature, if one more mole of B is added to this solution , the vapour pressure of the solution increases by 10 mm of Hg. Determine vapour pressures of A and B in their pure states.