The lubricating action of an oil is more if it possess:-

(1) High vapour pressure

(2) low vapour pressure

(3) High surface tension

(4) High density

Concept Questions :-

Relative Lowering of Vapour Pressure/ Vapour Pressure
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A 0.002 molar solution of NaCl having degree of dissociation of 90% at 27$°\mathrm{C}$, has osmotic pressure equal to :-

(1) 0.94 bar

(2) 9.4 bar

(3) 0.094 bar

(4) 9.4 X 10-4 bar

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Difficulty Level:

The relative lowering of vapour pressure caused by dissolving 71.3 g of a substance in 1000 g of water is 7.13 X 10-3. The molecular mass of the substance is :-

(1) 180

(2) 18

(3) 1.8

(4) 360

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Total vapour pressure of mixture of 1mol  and 2 mol  is 200 torr. In this case:

(1) there is positive deviation from Raoult's law

(2) there is negative deviation from Raoult's law

(3) there is no deviation from Raoult's law

(4) none of those

Concept Questions :-

Relative Lowering of Vapour Pressure/ Vapour Pressure
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

When 0.1 m CH3COOH is present in a solvent it shows elevation in boiling point of 0.75$°\mathrm{C}$. Acid dissociation constant will be -(Kb=5 K Kg mol-1) (1M =1m)

(1) 5 X 10-2

(2) 5 X 10-3

(3) 10-2

(4) 10-3

Concept Questions :-

Elevation of Boiling Point
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

Which of the following shows positive deviation from Raoult's law:

(i) Chloroform and acetone

(ii) Carbon disulphide and acetone

(iii) Ethanol and Acetone

(iv) Phenol and Aniline

(1) i and ii

(2) ii and iii

(3) i and iV

(4) ii and iv

High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A non-volatile solute is dissolved in a water. If its degree of association is 50%. What will be its freezing point when boiling point is 100.52$°\mathrm{C}$. [Kb=0.52 K kg mol-1, Kf=1.86K kg mol-1]

(1) -0.52 K

(2) -0.52$°\mathrm{C}$

(3) -1.86$°\mathrm{C}$

(4) 275.01 K

Concept Questions :-

Depression of Freezing Point
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

When 36 g of a solute having the emperical formula CH2O is dissolved in 1.2 kg of water, the solution freezes at -0.93$°\mathrm{C}$. What is the molecular formula of solute (Kf=1.86 kg K mol-1)

(1) C2H4O

(2) C2H2O2

(3) C2H4O3

(4) C2H4O2

Concept Questions :-

Depression of Freezing Point
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

How much oxygen is dissolved in 100ml water at 298K if partial pressure of oxygen is 0.5 atm and KH=1.4 X 10-3 M/atm ?

1. 22.4 mg

2. 22.4 g

3. 2.24 g

4. 2.24 mg

Concept Questions :-

Dalton’s Law of Partial Pressure/ Henry"s law
High Yielding Test Series + Question Bank - NEET 2020

Difficulty Level:

A solute x when dissolved in solvent associates to form a pentamer. The value of van't hoff factor (i) for the solute will be:-

(1) 0.5

(2)  5

(3) 0.2

(4) 0.1

Concept Questions :-

Van’t Hoff Factor