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Two liquids $A$ and $B$ form an ideal solution at temperature $T$ . When the total vapour pressure above the solution is $600$ Torr, then mole fraction of $A$ in the vapour phase is $0.35$ and in the liquid phase is $0.70$ .

If vapour pressure pure 'A' and pure 'B' are ${p_{A}}^{0} & {p_{B}}^{0}$ then find the value of $\frac{{p_{B}}^{0} - 2 {p_{A}}^{0}}{10}$ (in torr).

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Important Questions on Solutions

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

Vapour pressure of water at

293 K

17.535 mm Hg

. Calculate the vapour pressure of water at

293 K

when

25 g

of glucose is dissolved in

450 g

of water.

HARD

Chemistry>Physical Chemistry>Solutions>Raoult's Law

Which of the following statements about the composition of the vapour over an ideal 1 : 1 molar mixture of benzene and toluene is correct? Assume that the temperature is constant at

25^{o} C

. (Given vapour pressure data at

25^{o} C

, benzene = 12.8 kPa, toluene = 3.85 kPa)

EASY

Chemistry>Physical Chemistry>Solutions>Raoult's Law

9 gram anhydrous oxalic acid (mol. Wt. = 90) was dissolved in 9.9 moles of water. If vapour pressure of pure water is

P_{1}^{o}

the vapour pressure of solution is

HARD

Chemistry>Physical Chemistry>Solutions>Raoult's Law

Liquids

A

and

B

form ideal solution for all compositions of

A

and

B

25^{\circ} C

. Two such solutions with

0.25

and

0.50

mole fractions of

A

have the total vapor pressures of

0.3

and

0.4

bar, respectively. What is the vapor pressure of pure liquid

B

in bar?

HARD

Chemistry>Physical Chemistry>Solutions>Raoult's Law

Liquids

A

and

B

form an ideal solution in the entire composition range. At

350 K,

the vapour pressure of pure A and pure B are

7 \times 10^{3} Pa

and

12 \times 10^{3} Pa

, respectively. The composition of the vapour in equilibrium with a solution containing 40 mole percent of A at this temperature is:

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

An open beaker of water in equilibrium with water vapour is in a sealed container. When a few grams of glucose are added to the beaker of water, the rate at which water molecules :

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

Liquid

M

and liquid

N

form an ideal solution. The vapour pressures of pure liquids

M

and

N

are

450

and

700 m m H g,

respectively, at the same temperature. Then correct statements is:
(

x_{M} = M o l e f r a c t i o n o f {' M}^{'} i n s o l u t i o n;

x_{N} = M o l e f r a c t i o n o f {' N}^{'} i n s o l u t i o n;

y_{M} = M o l e f r a c t i o n o f {' M}^{'} i n v a p o u r p h a s e;

y_{N} = M o l e f r a c t i o n o f {' N}^{'} i n v a p o u r p h a s e;

)

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

A solution contains

5

moles of

X

and

5

moles of

Y

, and has a normal boiling point of

90 ° C

. The vapor pressure of pure

X

300 mm Hg

. What is the vapor pressure of pure

Y

at this temperature?

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

A solution is prepared by mixing

8.5

g of

{CH}_{2} {Cl}_{2}

and

11.95 g

{CHCl}_{3}

. If vapour pressure of

{CH}_{2} {Cl}_{2}

and

{CHCl}_{3}

298

K are

415

and

200

mm Hg respectively, the mole fraction of

{CHCl}_{3}

in vapour form is:

(M o l a r m a s s o f Cl = 35.5 g m o l^{- 1})

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

For a solution formed by mixing liquids

L

and

M

, the vapour pressure of

L

plotted against the mole fraction of

M

in solution is shown in the following figure, Here,

X_{L}

and

X_{M}

represent mole fractions of

L

and

M

, respectively, in the solution. The correct statement(s) applicable to this system is(are) -

Question Image

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

38.4 g

of unknown substance (molar mass

384 g {mol}^{- 1}

) and

116 g

of acetone is used to prepare a solution at

313 K

. If vapour pressure of pure acetone (molar mass

58 g {mol}^{- 1}

) is

0.842

atmosphere, what is the vapour pressure of solution ?

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

A solution at

20^{o} C

is composed of 1.5 mol of benzene and 3.5 mol of toluene. If the vapour pressure of pure benzene and pure toluene at this temperature are 74.7 torr and 22.3 torr respectively, then the total vapour pressure of the solution and the benzene mole fraction in equilibrium with it will be, respectively:

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

How many grams of glucose are required to prepare an aqueous solution of glucose having a vapor pressure of

23.324 mm Hg

25 ° C

100 g

of water? The vapour pressure of pure water at

25 ° C

23.8 mm Hg .

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

300 K

, the vapour pressure of a solution containing

1

mole of

n

-hexane and

3

moles of

n

-heptane is

550 mm

Hg

. At the same temperature, if one more mole of

n

-heptane is added to this solution, the vapour pressure of the solution increases by

10 mm

Hg

. What is the vapour pressure in

mmHg

n

- heptane in its pure state______?

HARD

Chemistry>Physical Chemistry>Solutions>Raoult's Law

Benzene and toluene form an ideal solution over the entire range of composition. The vapour pressure of pure benzene and toluene at $T (K)$ are $50 mmHg$ and $40 mmHg$ , respectively. What is the mole fraction of toluene in vapour phase when $117 g$ of benzene is mixed with $46 g$ of toluene?

(Molar mass of benzene and toluene are $78$ and $92 g {mol}^{- 1}$ , respectively)

HARD

Chemistry>Physical Chemistry>Solutions>Raoult's Law

The plot of total vapour pressure as a function of mole fraction of the components of an ideal solution formed by mixing liquids

X

and

Y

HARD

Chemistry>Physical Chemistry>Solutions>Raoult's Law

The vapour pressures of chloroform

({CHCl}_{3}),

dichloromethane

({CH}_{2} {Cl}_{2})

298 K

are

200 mmHg

and

415 mmHg

, respectively. An ideal solution is prepared by mixing

59.75 g

{CHCl}_{3}

and

21.25 g

{CH}_{2} {Cl}_{2}

, the mole fractions of chloroform and dichloromethane in vapour phase, respectively are

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

The vapour pressures of pure liquids

A

and

B

are

400

and

600 mm Hg

respectively at

298 K .

On mixing the two liquids, the sum of their volumes is equal to the volume of the final mixture. The mole fraction of liquid

B

0.5

in the mixture. The vapour pressure of the final solution, the mole fractions of components

A

and

B

in the vapour phase, respectively are

MEDIUM

Chemistry>Physical Chemistry>Solutions>Raoult's Law

A mixture of toluene and benzene boils at

100^{o} C

. Assuming ideal behaviour, the mole fraction of toluene in the mixture is closest to [Vapour pressures of pure toluene and pure benzene at

100^{o} C

are

0.742

and

1.800

bar respectively. 1 atm

= 1.013

bar]

HARD

Chemistry>Physical Chemistry>Solutions>Raoult's Law

Liquids A and B form ideal solution over the entire range of composition. At temperature

T

, equimolar binary solution of liquids A and B has vapour pressure

45 T o r r

. At the same temperature, a new solution of A and B having mole fractions

x_{A} and x_{B}

, respectively, has vapour pressure of

22.5 T o r r

. The value of

\frac{x_{A}}{x_{B}}

, in the new solution is ____.

(Given that the vapour pressure of pure liquid A is

20 Torr

at temperature

T

)

Important Questions on Solutions

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