21796.By dissolving 5 g substance in 50 g of water, the decrease in freezing point is 1.2°C. The molal depression is 1.85°C. The molecular weight of substance is
137.2
118.2
105.4
154.2
21797.The density (in g mL–1) of a 3.60 M sulphuric acid solution that is 29% H2SO4 (molar mass = 98 g mol–1) by mass will be
1.64
1.88
1.22
1.95
21798.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
1.78 M
2.00 M
2.05 M
2.22 M
21799.A solution of two liquids boils at a temperature more than the boiling point of either of them. Hence, the binary solution shows ______.
negative deviation from Raoult's law
positive deviation from Raoult's law
no deviation from Raoult's law
positive or negative deviation from Raoult's law depending upon the composition
21800.The molality of a urea solution in which 0.0100 g of urea, [(NH2)2CO] is added to 0.3000 dm3 of water at STP is
3.33 × 10–2 m
0.555 m
5.55 × 10–4 m
33.3 m
21801.A mixture of ethyl alcohol and propyl alcohol has vapour pressure of 290 mm at 300 K. The vapour pressure of propyl alcohol is 200 mm. If the mole fraction of ethyl alcohol is 0.6, its vapour pressure (in mm) at the same temperature will be
300
700
360
350
21803.A solution has 1 : 4 mole ratio of pentane to hexane. The vapour pressure of pure hydrocarbons at 20°C are 400 mm Hg for pentane and 120 mm Hg for hexane. The mole fraction of pentane in the vapour phase would be
0.200
0.549
0.786
0.478
21804.A solution of urea (mol. mass = 56 g mol–1) boils at 100.18°C at the atmospheric pressure. If Kf and Kb for water are 1.86 and 0.512 K kg mol–1 respectively, then the above solution will freeze at
0.654°C
–0.654°C
6.54°C
–6.54°C
21805.At 100ºC the vapour pressure of a solution of 6.5 g of a solute in 100 g water is 732 mm. If Kb = 0.52, the boiling point of this solution will be:
100ºC
102ºC
103ºC
101ºC
21806.Two solutions of a substance (non–electrolyte) are mixed in the following manner: 480 mL of 1.5 M first solution + 520 mL of 1.2 M second solution. What is the molarity of the final mixture?
1.20 M
1.50 M
1.344 M
2.70 M
21807.Equimolar solution in the same solvent have
same boiling point but different freezing point
same freezing point but different boiling point
same boiling point and same freezing point
different boiling point and different freezing point
21808.58.5 gm of NaCl and 180 gm of glucose were separately dissolved in 1000 ml of water. Identify the correct statement regarding the elevation of boiling point (b.p.) of the resulting solutions.
NaCl solution will show higher elevation of b.p.
Glucose solution will show higher elevation of b.p.
Both the solutions will show equal elevation of b.p.
The b.p. elevation will be shown by neither of the solutions
21809.250 ml of a Sodium carbonate solution contains 2.65 grams of Na2CO3. If 10 ml of this solution is diluted to one litre, what is the concentration of the resultant solution? (molecular weight of Na2CO3 = 106)
0.1 M
0.001 M
0.01 M
10–4 M
21810.250 ml of a sodium carbonate solution contains 2.65 grams of Na2CO3. 10 ml of this solution is added to x ml of water to obtain 0.001 M Na2CO3 solution. What is the value of x in ml?
(Molecular weight of Na2CO3 = 106)
(Molecular weight of Na2CO3 = 106)
1000
990
9990
90
21811.A solution of acetone in ethanol
shows a positive deviation from Raoult's law
behaves like a near ideal solution
obeys Raoult's law
shows negative deviation from Raoult's law
21812.25.3 g of sodium carbonate, Na2CO3 is dissolved in enough water to make 250 ml of solution. If sodium carbonate dissociates completely, molar concentration of sodium Ion, Na+ and carbonate ions, CO2–
3 are respectively (Molar mass of Na2CO3 = 106 g mol–1)
3 are respectively (Molar mass of Na2CO3 = 106 g mol–1)
1.90 M and 1.910 M
0.477 M and 0.0477 M
0.955 M and 1.910 M
1.910 M and 0.955 M
21813.A mixture of ethane and ethene occupies 41 L at 1 atm and 500 K. The mixture reacts completely with 10.3 mole of O2 to produce CO2 and H2O. The mole fractions of ethane and ethene in the mixture are (R = 0.082 L atm K–1mol–1) respectively
0.50, 0.50
0.75, 0.25
0.67, 0.33
0.25, 0.75
21814.Which has minimum osmotic pressure?
200 mL of 2 M NaCl solution
200 mL of 1 M glucose solution
200 mL of 2 M urea solution
All have same osmotic pressure
21815.On mixing, heptanes and octane form an ideal solution. At 373 K, the vapour pressures of the two liquid components (heptanes and octane) are 105 kPa and 45 kPa respectively. Vapour pressure of the solution obtained by mixing 25.0 g of heptanes and 35 g of octane will be (molar mass of heptanes = 100 g mol–1 and of octane = 114 g mol–1)
96.2 kPa
144.5 kPa
72.0 kPa
36.1 kPa