Molality is the most inconvenient way of expressing concentration because it_______________________.
Has no unit
Is very difficult to find out
Involves difficult calculations
Involves the measurement of weight of liquids
A solution of urea (mol.mass 56 g mol-1) boils at 100.18oC at the atmosphere pressure. If kf and kb for water are 1.86 and 0.51 2 K kg mol-1 respectively, the above solution will freeze at.
-6.54oC
6.54oC
0.654oC
-0. 654oC
Concentrated aqueous sulphuric acid is 98% H2SO4 by mass and has a density of 1.80 g mL-1. Volume of acid required to make one litre of 0.1 M H2SO4 solution is
11.10 mL
16.65 ml
22.20 mL
5.55 mL
Pure water can be obtained from sea water by
Centrifugation
Plasmolysis
Reverse osmosis
Sedimentation
The better concentration term when the amount of solute is very small is_______________
Molarity
Molality
Parts per million
Mole fraction
If a hydrated crystal has vapour pressure greater than that of water vapour in the atmosphere, the crystal is __________________
Hygroscopic
Efflorescent
Deliquescent
Phosphorescent
The vapour pressure, at a given temperature, of an ideal solution containing 0.2 mole of a non volatile solute and 0.8 mole of solvent is 60 mm of Hg. The vapour pressure of the pure solvent at the same temperature is.
150 mm of Hg
60 mm of Hg
75 mm of Hg
120 mm of Hg
A solution of acetone in ethanol
Shows a negative deviation from Raoult's law
Shows a positive deviation from Raoult's law
Hehave like a near ideal solution
Obeys Raoult's law
If 0.15 g of solute, dissolved in 15 g of solvent, is boiled at a temperature higher by 0.216oC, than that of the pure solvent, the molecular weight of the substance is ______________(molal elevation constant for the solvent is 2.16oC).
1.01
10
10.1
100
Which of the following colligative property can provide molar mass of proteins (or polymers or colloids) with greatest precision?
Osmotic pressure
Elevation in boiling point
Depression in freezing point
Relative lowering of vapour pressure