Lowering in vapour pressure is the highest for [Roorkee 1989; BHU 1997]

(1) 0.2m urea

(2) 0.1 m glucose

(3) 0.1m MgSO4

(4) 0.1m BaCl2

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Difficulty Level:

Vapour pressure of CCl4 at 25°C is 143 mm Hg 0.5 g of a non-volatile solute (mol. wt. 65) is dissolved in 100 ml of CCl4. Find the vapour pressure of the solution. (Density of $CC{l}_{4}=1.58\text{\hspace{0.17em}}g/c{m}^{3}\right)$ [CBSE PMT 1996]

(1) 141.93 mm

(2) 94.39 mm

(3) 199.34 mm

(4) 143.99 mm

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Difficulty Level:

The vapour pressure of pure benzene and toluene are 160 and 60 torr respectively. The mole fraction of toluene in vapour pressure in contact with equimolar solution of benzene and toluene is [Pb. CET 1988]

(1) 0.50

(2) 0.6

(3) 0.27

(4) 0.73

Concept Questions :-

Concentration Term and Numericals
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Difficulty Level:

The vapour pressure of a solvent decreases by 10 mm of mercury when a non-volatile solute was added to the solvent. The mole fraction of the solute in the solution is 0.2. What should be if the decrease in vapour pressure is to be 20 mm of mercury then the mole fraction of the solvent is [CBSE PMT 1998]

(1) 0.8

(2) 0.6

(3) 0.4

(4) None

Concept Questions :-

Concentration Term and Numericals
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Difficulty Level:

The vapour pressure of a solvent A is 0.80 atm. When a non-volatile substance B is added to this solvent its vapour pressure drops to 0.6 atm. the mole fraction of B in the solution is [MP PMT 2000]

(1) 0.25

(2) 0.50

(3) 0.75

(4) 0.90

Concept Questions :-

Relative Lowering of Vapour Pressure/ Vapour Pressure
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Difficulty Level:

Osmotic pressure is 0.0821 atm at a temperature of 300 K. find concentration in mole/litre [Roorkee 1990]

(1) 0.033

(2) 0.066

(3) 0.33 × 10–2

(4) 3

Concept Questions :-

Osmosis and Osmotic Pressure
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Difficulty Level:

The osmotic pressure of 5% (mass-volume) solution of cane sugar at 150°C (mol. mass of sugar = 342) is [BHU 1995]

(1) 4 atm

(2) 5.07 atm

(3) 3.55 atm

(4) 2.45 atm

Concept Questions :-

Osmosis and Osmotic Pressure
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Difficulty Level:

A solution containing 3.3 g of a substance in 125 g of benzene (b.p. 80°C) boils at 80.66°C. If Kb for one litre of benzene is 3.28°C, the molecular weight of the substance shall be [CPMT 1992]

(1) 127.20

(2) 131.20

(3) 137.12

(4) 142.72

Concept Questions :-

Elevation of Boiling Point
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Difficulty Level:

The molal b.p. constant for water is $0{.513}^{o}C\text{\hspace{0.17em}}kg\text{\hspace{0.17em}}mo{l}^{-1}$. When 0.1 mole of sugar is dissolved in 200 g of water, the solution boils under a pressure of 1 atm at [AIIMS 1991]

(1) 100.513°C

(2) 100.0513°C

(3) 100.256°C

(4) 101.025°C

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Difficulty Level:

An aqueous solution containing 1 g of urea boils at 100.25°C. The aqueous solution containing 3 g of glucose in the same volume will boil at [BHU 1994, CBSE 2000]

(1) 100.75°C

(2) 100.5°C

(3) 100°C

(4) 100.25°C

Concept Questions :-

Osmosis and Osmotic Pressure