A solution has 1 : 4 mole ratio of pentane to hexane. The vapour pressure of the pure hydrocarbons at 20oC are 440 mm of Hg for pentane and 120 mm of Hg for hexane. The mole fraction of pentane in the vapour phase would be
0.549
0.200
0.786
0.478
During osmosis, flow of water through a semi permeable membrane is
From solution having higher concentration only
From both sides of semi-permeable membrane with equal flow rates
From both sides of semi-permeable membrane with unequal flow rates
From solution having lower concentration only
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
The vapour pressure of a solvent decreased by 10 mm in two columns 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 the mole fraction of the solvent if the decrease in the vapour pressure is to be 20mm of mercury?
0.8
0.6
0.4
0.2
Which one of the following salts will have the same value of van't Hoff factor (i) as that of K4[Fe(CN)6]?
Al2(SO4)3
NaCI
AI(NO3)3
Na2SO4
The lowering of vapour pressure of the solvent takes place on dissolving a non-volatile solute because______________________
the surface tension of the solution decreases
the density of the solution increases
the molecules of the solvent on the surface are replaced by the molecules of the solute
the viscosity of the solution increases
1.00g of a non- electrolyte solute (molar mass 250g mol-1) was dissolved in 51.2 g of benzene. If the freezing point depression constant, kf of benzene is 5.12 K kg mol-1, the freezing point of benzene will be lowered by.
0.4 K
0. 3 K
0.5 K
0. 2K
A-B attraction force is greater than A - A and B- B
A - B attraction force is less than A - A and B - B
A- B attraction force remains same as A - A and B - B
Volume of solution is different from sum of volumes of solute and solvent
The vapour pressure of two liquids P and Q are 80 and 60 torr, respectively. The total vapour pressure of solution obtained by mixing 3 moles of p and 3 mols of Q would be.
140 torr
20 torr
68 torr
72 torr
If a hydrated crystal has vapour pressure greater than that of water vapour in the atmosphere, the crystal is __________________
Hygroscopic
Efflorescent
Deliquescent
Phosphorescent
