EASY

Earn 100

Define freezing point of liquid.

Important Questions on Solutions

HARD

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

5 g

{Na}_{2} {SO}_{4}

was dissolved in

x g

H_{2} O

. The change in freezing point was found to be

3 {.82}^{o} C

. If

{Na}_{2} {SO}_{4}

81.5 %

ionised, the value of

x

(

K_{f}

for water

= 1 {.86}^{o} C kg {mol}^{- 1}

) is approximately:

(molar mass of

S = 32 g {mol}^{- 1}

and that of

Na = 23 g {mol}^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

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?

MEDIUM

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

The freezing point of benzene decreases by ${0.45}^{°} C$ on adding $0.2 g$ of acetic acid to $20 g$ of benzene. If acetic acid associates to form a dimer in benzene, then what is the percentage association of acetic acid in benzene?

$(K_{f} for benzene = 5 .12 K kg {mol}^{- 1})$

MEDIUM

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

For

1 molal

aqueous solution of the following compounds, which one will show the highest freezing point?

EASY

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

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.

EASY

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

If molality of the dilute solution is doubled, the value of molal depression constant

(K_{f})

will be

MEDIUM

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

The elevation in boiling point for

1

molal solution of glucose is

2 K

. The depression in freezing point for

2

molal solution of glucose in the same solvent is

2 K .

The relation between

K_{b}

and

K_{f}

is:

MEDIUM

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

How much amount of

N a C l

should be added to

600 g

of water

(ρ = 1.00 g / m L)

to decrease the freezing point of water to

- 0.2^{o} C

? ________. (The freezing point depression constant for water

= 2 K k g {m o l}^{- 1}

)

MEDIUM

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

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

Question Image

The boiling point of the solvent is _____°C.

MEDIUM

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

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>Depression of Freezing Point

Pure water freezes at

273 K

and

1 bar

pressure. The addition of

34.5 g

of ethanol to

500 g

of water changes the freezing point of the solution. Use the freezing point depression constant of water as

2 K kg {mol}^{- 1}

. The figures shown below represent the plots of vapour pressure (

V . P .

) versus temperature (

T

). [Molecular weight of ethanol is 46 g

46 g {mol}^{- 1}

]

Among the following, the option representing a change in the freezing point is

EASY

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

A pressure cooker reduces cooking time for food because

HARD

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

On dissolving $0.5 g$ of a non-volatile non-ionic solute to $39 g$ of benzene, its vapor pressure decreases from $650 m m H g$ to $640 m m H g .$ The depression of freezing point of benzene (in $K$ ) upon addition of the solute is _______

(Given data: Molar mass and the molal freezing point depression constant of benzene are $78 g m o l^{- 1}$ and $5.12 K k g m o l^{- 1},$ respectively)

Give your answer up to three significant figures.

HARD

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

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

MEDIUM

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

Molal depression constant for a solvent is

4.0 K k g m o l^{- 1} .

The depression in the freezing point of the solvent for

0.03 m o l k g^{- 1}

solution of

K_{2} S O_{4}

is:
(Assume complete dissociation of the electrolyte)

EASY

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

5 %

solution (by mass) of cane sugar in water has freezing point of

271 K

. Calculate the freezing point of

5 %

glucose in water if freezing point of pure water is

273.15 K

EASY

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

Of the following

0.10 m

aqueous solutions, which one will exhibit the largest freezing point depression?

MEDIUM

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

A solution containing

62 g

ethylene glycol in

250 g

water is cooled to

- 10^{o} C

. If

K_{f}

for water is

1.86 K kg {mol}^{- 1}

, the amount of water (in

g

) separated as ice is:

EASY

Chemistry>Physical Chemistry>Solutions>Depression of Freezing Point

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>Depression of Freezing Point

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

1

molal aqueous

KI

solution at same temperature?

Define freezing point of liquid.

Important Questions on Solutions

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