The vapour density of undecomposed N2O4 is 46. When heated, vapour density decreases to 24.5 due to its dissociation to NO2. The percent dissociation of N2O4 at the final temperature is:
1. 87
2. 60
3. 40
4. 70
The molal depression constant for water=1.85 deg/molal and for benzene is 5.12 deg/molal. If the ratio of the latent heats of fusion of benzene to water is 3:8, calculate the freezing point of benzene.
1. 6.75
2. 5.12
3. 8.97
4. 6.1
Which of the following colligative properties is associated with the concentration term 'molarity'?
1. Lowering of vap.pressure
2. Osmotic pressure
3. Depression in freezing point
4. Elevation in boiling point
The vapour pressure of a dilute aqueous solution of glucose is 750 mm of Hg at 373 K. The mole fraction of solute in the solution is-
1. 1/10
2. 1/76
3. 1/7.6
4. 1/35
Which pair of solutions is likely to exhibit isotonicity at a constant temperature?
1. 0.1 (M) Urea and 0.1 (M) NaCl
2. 0.1 (M) Urea and 0.2 (M) MgCl2
3. 0.1 (M) NaCl and 0.1 (M) Na2SO4
4. 0.1 (M) Ca(NO3)2 and 0.1 (M) Na2SO4
The latent heat of vapourisation of water is 540 cal g-1 at 100. Kb for water is
1. 0.56 K.mole-1
2. 1.86 K.mole-1
3. 0.51 K.mole-1
4. 5.12 K.mole-1
Which of the following aqueous solution has osmotic pressure nearest to that an equimolar solution of K4[Fe(CN)6]?
1. Na2SO4
2. BaCl2
3. Al2(SO4)3
4. C12H22O11
The ratio of the vapour pressure of a solution to the vapour pressure of the solvent is
1. Equal to the mole fraction of the solvent
2. Proportional to the mole fraction of the solute
3. Equal to the mole fraction of the solute
4. None of the above
A two phase system consisting of a liquid dispersed in another liquid is known as-
1. Foam
2. Suspension
3. Emulsion
4. Mist
The partial pressure of ethane over a saturated solution containing 6.56 X 10-2 g of ethane is 1 bar. If the solution contains 5.00 X 10-2 g of ethane, then what shall be the partial pressure of the gas?
1. 0.76 bar
2. 0.16 bar
3. 1.16 bar
4. 3.12 bar
An aqueous solution
of hydrochloric acid -
1. Obeys Raoult's law
2. Shows negative deviations from Raoult's law
3. Shows positive deviations from Raoult's law
4. Obeys Henry's law at all compositions
Osmotic pressure of equimolar solution of BaCl2, NaCl and glucose will be in the order -
1. BaCl2 > NaCl > glucose
2. glucose > NaCI > BaCl2
3. NaCl > BaCl2 >glucose
4. NaCl> glucose > BaCl2
The boiling point of an azeotropic mixture of water and ethanol is less than that of water and ethanol. The mixture shows
(1) No deviation from Raoult's law
(2) Positive deviation from Raoult's law
(3) Negative deviation from Raoult's law
(4) That the solution is unsaturated
20g of naphthoic acid (C11H8O2) dissolved in 50g of benzene (Kf=1.72 K Kg mol-1) shows a depression in freezing point of 2K. The Vant Hoff factor is?
1. 0.5
2. 0.1
3. 2
4. 3
20 g of naphthoic acid(C11H8O2) dissolved in 50 g of benzene(Kf=1.72 K Kg mol-1) shows a depression in freezing point of 2 K. The vant Hoff factor is ?
(1) 0.5
(2) 0.1
(3) 2
(4) 3
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
1. There is a positive deviation from Raoult's law.
2. There is a negative deviation from Raoult's law.
3. There is no deviation from Raoult's law.
4. None of the above.
One litre aqueous solution of sucrose (molar mass = 342 g/mol) weighing 1015 g is found to record an osmotic pressure of 4.8 atm at 293K. What is the molality of the sucrose solution ? (R= 0.0821 L atm K-1 mol-1) :
(1) 0.84
(2) 0.21
(3) 0.42
(4) 0.63
The van't Hoff factor of a 0.005 M aqueous solution of KCl is 1.95. The degree of ionisation of KCl is-
1. 0.95
2. 0.97
3. 0.94
4. 0.96
K4[Fe(CN)6] is 60% ionised. Then the value of Van't Hoff factor is
1. 1.6
2. 2.4
3. 3
4. 3.4
The temperature dependent term among the following is -
1. | Molality | 2. | Molarity |
3. | Mole fraction | 4. | Weight percentage |
Which one is not equal to zero for an ideal solution?
1. ΔHmix
2. ΔSmix
3. ΔVmix
4. ΔP=PObserved-PRaoult
Which one of the following elctrolytes has the same value of van't Hoff's factor(i) as
that of Al2(SO4)3 (if all are 100% ionised)?
1. K2SO4
2. K3[Fe(CN)6]
3. Al(NO3)3
4. K4[Fe(CN)6]
Of the following 0.10 m aqueous solutions, which one will exhibit the largest freezing
point depression?
1. KCl
2. C6H12O6
3. Al2(SO4)3
4. K2SO4
The van't Hoff factor, i for a compound which undergoes dissociation in one solvent and
association in other solvent is respectively.
1. less than one and less than one
2. greater than one and less than one
3. greater than one and greater than one
4. less than one and greater than one
A solution containing 10 g per dm3 of urea (molecular mass = 60 g mol-1) is isotonic with a 5% solution of a non-volatile solute. The molecular mass of this non-volatile solute is:
(1) 250 g mol-1
(2) 300 g mol-1
(3) 350 g mol-1
(4) 200 g mol-1
1.00 g of a non-electrolyte solute (molar mass 250g/mol) 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:-
(1) 0.4 K
(2) 0.3 K
(3) 0.5 K
(4) 0.2 K
Consider equimolal aqueous solutions of NaHSO4 and NaCl with Tb and b as their respective boiling point elevations. The value of will be :
(1) 1
(2) 1.5
(3) 3.5
(4) 3
15 g of methyl alcohol is dissolved in 35 g of water. The weight percentage of methyl alcohol in solution is
1. 30%
2. 50%
3. 70%
4. 75%
The seawater sample contains 5.8 × 10–3 g of dissolved oxygen per kilogram of the sample. The concentration of oxygen in parts per million is-
1. 5.8 ppm
2. 58.5 ppm
3. 0.58 ppm
4. 0.05 ppm
Amount of NaOH present in 200 ml of 0.5 N solution is
(1) 40 g
(2) 4 g
(3) 0.4 g
(4) 4.4 g
50 ml of of 12 N HCl and 40 ml of were mixed together and the volume of the mixture was made 1000 ml by adding water. The normality of the resulting solution will be
(1) 1 N
(2) 2 N
(3) 3 N
(4) 4 N
Equal volumes of and 0.2 M NaCl are mixed. The concentration of ions in the mixture will be
(1) 0.1 M
(2) 0.05 M
(3) 0.2 M
(4) 0.15 M
Amount of oxalic acid in grams that is required to obtain 250 ml of a semi-molar solution is
(1) 17.25 g
(2) 17.00 g
(3) 15.75 g
(4) 15.00 g
Volume of 10 M HCl should be diluted with water to prepare 2.00 L of 5 M HCl is
(1) 2 L
(2) 1.5 L
(3) 1.00 L
(4) 0.5 L
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
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
The osmotic pressure of 5 % (mass-volume) solution of cane sugar at 150 °C (mol. mass of sugar = 342 g/mole) is:
1. | 4 atm | 2. | 5.07 atm |
3. | 3.55 atm | 4. | 2.45 atm |
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
1. 127.20
2. 131.20
3. 137.12
4. 142.72
The molal b.p. constant for water is . When 0.1 mole of sugar is dissolved in 200 g of water, the solution boils under a pressure of 1 atm at
(1) 100.513°C
(2) 100.0513°C
(3) 100.256°C
(4) 101.025°C
What is the molality of the solution of a certain solute in a solvent if there is a freezing point depression of 0.184° and if the freezing point constant is 18.4 K kg mol−1
1. 0.01
2. 1.00
3. 0.001
4. 100
The molar freezing point constant for water is 1.86°C/mole. If 342 g of cane sugar is dissolved in 1000 g of water, the solution will freeze at
1. –1.86°C
2. 1.86°C
3. –3.92°C
4. 2.42°C
The depression in freezing point of 0.01 M aqueous solutions of urea, sodium chloride and sodium sulphate is in the ratio of [Roorkee 1990; DCE 1994]
(1) 1 : 1 : 1
(2) 1 : 2 : 3
(3) 1 : 2 : 4
(4) 2 : 2 : 3
The Van't Hoff factor for 0.1 M solution is 2.74. The degree of dissociation is [IIT 1999]
(1) 91.3%
(2) 87%
(3) 100%
(4) 74%
Dissolving 120 g of urea (mol. wt. 60) in 1000 g of water gave a solution of density 1.15 g/mL. The molarity of the solution is:
1. 7.78 M
2. 2.00 M
3. 2.05 M
4. 2.22 M