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The vapour pressure of ethanol is $115$ torr at $34.9 ° C$ . if ${ΔH}_{vap}$ of ethanol is $38.6 kJ / mol$ . Calculate the temp. $({}^{\circ}C)$ when then vapour pressure is $760$ torr.

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Important Questions on Solutions

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Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

18 g

glucose

(C_{6} H_{12} O_{6})

is added to

178.2 g

water. The vapour pressure of water (in torr) for this aqueous solution is:

MEDIUM

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

Consider the following liquid - vapour equilibrium.

L i q u i d ⇌ V a p o u r

Which of the following relations is correct?

EASY

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

The mass of a non-volatile, non-electrolyte solute (molar mass

= 50 g {mol}^{- 1}

) needed to be dissolved in

114 g

octane to reduce its vapour pressure by

75 %

, is:

MEDIUM

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

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;

)

EASY

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

Identify which liquid will have a higher vapour pressure at

90 ℃

if the boiling points of two liquids

A

and

B

are

140 ℃

and

180 ° C

, respectively.

MEDIUM

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

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

HARD

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

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

)

MEDIUM

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

Relative lowering of vapour pressure of a dilute solution of glucose dissolved in

1 kg

of water is

0.002

. The molality of the solution is

MEDIUM

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

A solution is prepared by mixing

40 g

{CHCl}_{3}

with

17 g

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

298 K

and

281 mmHg

pressure. Assuming validity of Roult's law, the vapour pressure of pure

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

(in

mmHg

) at

298 K

is [Vapour pressure of pure

{CHCl}_{3}

298 K = 200 mmHg

; molar mass of

{CHCl}_{3} = 120 g {mol}^{- 1}

; molar mass of

{CH}_{2} {Cl}_{2} = 85 g {mol}^{- 1}

]

MEDIUM

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

The vapour pressure vs. temperature curve for a solution solvent system is shown below.

Question Image

The boiling point of the solvent is _____°C.

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Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

At room temperature, a dilute solution of urea is prepared by dissolving

0.60 g

of urea in

360 g

of water. If the vapour pressure of pure water at this temperature is

35 m m H g

, lowering of vapour pressure will be:
(molar mass of urea

= 60 g m o l^{- 1}

)

EASY

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

A pressure cooker reduces cooking time for food because

EASY

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

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>Lowering of Vapour Pressure

Choose the correct statement with respect to the vapour pressure of a liquid among the following :

EASY

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

Two open beakers one containing a solvent and the other containing a mixture of that solvent with a non volatile solute are together sealed in a container. Over time:

EASY

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

A set of solutions is prepared using

180 g

of water as a solvent and

10 g

of different non-volatile solutes

A, B

and

C

. The relative lowering of vapour pressure in the presence of these solutes are in the order [Given, molar mass of

A = 100 g {mol}^{- 1}; B = 200 g {mol}^{- 1}; C = 10, 000 g {mol}^{- 1}

]

MEDIUM

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

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>Lowering of Vapour Pressure

100^{o} C

the vapour pressure of a solution of 6.5 g of a non-volatile solute in 100 g water is 732 mm. If

K_{b} = 0.52

, the boiling point of this solution will be:

EASY

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

The vapour pressures of

A

and

B

25 ° C

are

90 mmHg

and

15 mm Hg

respectively. If

A

and

B

are mixed such that the mole fraction of

A

in the mixture is

0.6,

then the mole fraction of

B

in the vapour phase is

x \times 10^{- 1} .

The value of

x

is (Nearest integer)

MEDIUM

Chemistry>Physical Chemistry>Solutions>Lowering of Vapour Pressure

Which of the following changes will cause increase in vapour pressure of

1

molal aqueous

KI

solution at same temperature?

The vapour pressure of ethanol is 115 torr at 34.9°C. if ΔHvap of ethanol is 38.6 kJ/mol. Calculate the temp. C∘ when then vapour pressure is 760 torr.

Important Questions on Solutions

Learn and Prepare for any exam you want !

The vapour pressure of ethanol is $115$ torr at $34.9 ° C$ . if ${ΔH}_{vap}$ of ethanol is $38.6 kJ / mol$ . Calculate the temp. $({}^{\circ}C)$ when then vapour pressure is $760$ torr.