SOLUTIONS – 7

1) The vapour pressure of a solution of 5 g of non-electrolyte in 100 g of water at a particular temperature is . The vapour pressure of pure water at that temperature is . The molecular weight of the solute is
a) 180
b) 90
c) 270
d) 200

2) The vapour pressure of a solvent decreases by 10 mm 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 vapour pressure is to be 20 mm of mercury?
a) 0.8
b) 0.6
c) 0.4
d) 0.4

3) 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
a) 0.25
b) 0.50
c) 0.75
d) 0.90

4) Which one of the following is not a colligative property for a sucrose solution?
a) Decrease in the vapour pressure of water
b) Increase in the boiling point of water
c) Decrease in the freezing point of water
d) Decrease in the angle of rotation on adding dil. HCI

5) The molecular weight of a non-volatile solute can be determined by
a)
b) Graham’s law of diffusion
c)
d)

6) 8 g of HBr is added to 100 g of . The freezing point will be
a)
b)
c)
d)

7) Two solutions A and B are separated by a semipermeable membrane. As a result of osmosis, the level of solution A is found to rise. It implies that
a) Solution A is more concentrated than solution B
b) Solution B is more concentrated than solution A
c) The solute molecules of A are smaller than those of B
d) The solute molecules of B are smaller than those of A

8) Two solutions A and B are separated by a semipermeable membranes. No osmosis occurs. This means that the
a) Solutions are saturated
b) Solute particles in them are too big in size
c) Solutions are isotonic
d) Solvent molecules are too big in size

9) The outer shell of an egg was dissolved in hydrochloric acid and then placed in concentrated NaCl solution. Which one of the following will happen?
a) The egg will swell
b) The egg will shrink
c) Nothing will happen to the egg
d) The inside of the egg will become saltish

10) The value of osmotic pressure does not depend upon the
a) Concentration of the solution
b) Temperature of the solution
c) Number of particles of the solute present
d) Structure of the solute particles

11) Two aqueous solutions are separated by a semi-permeable membrane. has lower vapour pressure than . Then
a)
b)
c)
d) no flow will take place

12) If dry air is passed through two bulbs, one containing the solvent and the other containing the solution, the decrease in weight will be
a) more in the solvent bulb
b) more in the solution bulb
c) same in both the bulbs
d) nil in both the bulbs

13) The best colligative property used for the determination of molecular masses of polymers is the
a) Relative lowering of vapour pressure
b) Elevation in boiling point
c) Depression in freezing point
d) Osmotic pressure

14) Osmotic pressure is preferred over other colligative properties for determination of molecular masses of polymers because
a) The osmotic pressure of polymer solutions is very high
b) Polymer solutions have no fixed boiling point or freezing point
c) Osmotic pressure is easy to measure
d) Osmotic pressure can be measured more accurately than other colligative properties

15) A solution which has a lower osmotic pressure as compared to other solutions is known as
a) Hypotonic
b) Hypertonic
c) Isotonic
d) None of the above

16) @ The boiling point of 0.1 molal solution will be (Given for water = kg )
a)
b)
c)
d)

17) KBr is 80% dissociated in solution (Kt for water is 1.860C). The freezing point of a 0.5 molal solution is
a) 273 K
b) 277 K
c) 271.326 K
d) 269 K

18) A 0.1 molal aqueous solution of sodium bromide freezes at at atmospheric pressure. for water is . The percentage of dissociation of the salt in solution is
a) 90
b) 80
c) 58
d) 98

19) In a certain solvent, phenol dimerizes to the extent of 60%. Its observed molecular mass in that solvent should be
a) >94
b) =94
c) <94
d) unpredictable

20) The vants Hoff factor for 0.1 M solution is 2.74. The degree of dissociation is
a) 91.3%
b) 87%
c) 100%
d) 74%

21) The values of observed and calculated molecular weights of silver nitrate are 92.64 and 170 respectively. The degree of dissociation of silver nitrate will be
a) 60%
b) 83.5%
c) 46.7%
d) 60.23%

22) A solution which has a higher osmotic pressure as compared to another solution is known as
a) Hypotonic
b) Hypertonic
c) Isotonic
d) Normal

23) Blood has been found to be isotonic with
a) Concentrated NaCl solution
b) Very dilute NaCl solution
c) Normal saline solution
d) Saturated NaCl solution

24) Which statement is incorrect about osmotic pressure (P), volume (V) and temperature (T)?
a)
b)
c)
d) PV is constant if V is constant

25) What will happen if sugar beet is placed in concentrated sugar solution?
a) Sugar beet will lose water from its cells
b) Sugar beet will absorb water from solution
c) Sugar beet will neither absorb nor lose water
d) Sugar beet will dissolve in solution

26) A plant cell shrinks when it is kept in
a) A hypotonic solution
b) A hypertonic solution
c) A solution isotonic with cell sap
d) Water

27) An aqueous solution of urea freezes at 272.8 K. An equimolar solution of acetic acid in water will freeze at
a) 272.8 K
b) 272.79 K
c) 272.81 K
d) 272.6 K

28) Which one of the following statements is incorrect?
a) The greater the lowering of vapour pressure, the greater is the boiling point of the solution
b) The greater the lowering of vapour pressure, the greater is the freezing point of the solution
c) At the freezing point, the solute and the solvent have same vapour pressure
d) The unit of molal depression constant is Km-1

29) On freezing an aqueous solution of sugar, the solid that starts separating out is
a) Sugar
b) Ice
c) Solution with the same composition
d) Solution with a different composition

30) @ The molal elevation constant and molal depression constant for water are respectively
a) 0.52, 1.86
b) 1.86, 0.52
c) 1.52, 0.86
d) 0.86, 1.52

31) Glucose solution is to be injected into the blood stream. It must have the same ………… as the blood stream
a) Molarity
b) Vapour pressure
c) Osmotic pressure
d) Viscosity

32) The molecular mass of a solute cannot be calculated by one of the following relations.
a)
b)
c)
d)

33) At high altitudes the boiling point of water is lower because the
a) Atmospheric pressure is low
b) Temperature is low
c) Atmospheric pressure is high
d) None of these

34) The molal depression constant is calculated from the enthalpy of fusion and the boiling point of the solvent using the ratio
a)
b)
c)
d)

35) Which of the following aqueous solution do you expect to have the lowest freezing point?
a)
b) 0.1 m NaCl
c)
d)

36) Which of the following solutions will have the highest boiling point?
a)
b)
c) 0.1 M NaCl
d)

37) Solutions A, B, C and D are respectively 0.1 M glucose, 0.05 M NaCl, 0.05 M and 0.1 M . Which one of the following pairs is isotonic?
a) A and B
b) B and C
c) A and D
d) A and C

38) The vant Hoff factor (i) is the ratio of
a) the observed molecular mass to the calculated
b) the observed colligative property to the calculated value
c) the calculated colligative property to the observed value
d) the number of moles dissociated to the total number of moles taken

39) The vant Hoff factor for a dilute solution of glucose is
a) zero
b) 1
c) 1.5
d) 2.0

40) The depression in freezing point of 0.1 M aqueous solutions of HCI, are in the ratio
a) 1:1:1
b) 1:2:3
c) 1:1:1.5
d) 2:4:3

41) Which of the following solutions will have the maximum lowering of vapour pressure at 300 K?
a) 1 M NaCl
b)
c) 1 M sucrose
d) 1 M Phenol

42) Assuming complete dissociation, which one of the following will have a vant Hoff factor of 2?
a)
b) Sucrose
c)
d) Lead nitrate

43) The ratio of the colligative properties of NaCl solution to that of the glucose solution of the same molality is about
a) 0.5
b) 1
c) 1.5
d) 2

44) @ for water is 0.52 K/m. Then 0.1 M solution of NaCl will boil approximately at
a)
b)
c)
d)

45) If a substance undergoes association or dissociation in the solution and i is the Vant Hoff factor, then the expression for osmotic pressure is
a) I p = CRT
b)
c) PV= inRT
d) PV = nRT/I

46) The substance A when dissolved in the solvent B shows a molecular mass corresponding to . The vant Hoff factor will be
a) 1
b) 2
c) 3
d) 1/3

47) Benzoic acid undergoes dimerisation in benzene solution, the vant Hoff factor i is related to the degree of association x of the acid as
a) i = (1 -x)
b) i = (1 + x)
c) i = (1 – x/2 )
d) i = (1 +x/2)

48) The freezing point of equimolal aqueous solutions will be highest for
a)
b)
c)
d)

49) Which one of the following statements is incorrect?
a) A solution freezes at a lower temperature than the pure solvent
b) A solution boils at a higher temperature than the pure solvent
c) 0.1 M NaCl solution and 0.1 M sugar solution have the same boiling point
d) Osmosis cannot take place without a semipermeable membrane.

50) The molecular weight of KCI determined by the osmotic pressure method will be
a) the same as the normal molecular weight
b) Higher than the normal molecular weight
c) Lower than the normal molecular weight
d) Cannot be predicted unless data are given

51) Which of the following compounds corresponds to vant Hoff factor (i) to be equal to 2 for a dilute solution?
a)
b)
c) Sugar
d)

52) At low concentrations, the statement that equimolal solutions under a given set of experimental conditions have equal osmotic pressure is true for
a) all solutions
b) Solutions of non-electrolytes only
c) Solutions of electrolytes only
d) None of these

53) Which of the following is a colligative property?
a) Surface tension
b) Viscosity
c) Osmotic pressure
d) Boiling point

54) The molal elevation constant is the ratio of the elevation in boiling point to
a) Molarity
b) Molality
c) Mole fraction of solute
d) Mole fraction of solvent

55) Which of the following would exert the maximum osmotic pressure?
a) Decinormal aluminium sulphate
b) Decinormal barium chloride
c) Decinormal sodium chloride
d) A solution obtained by mixing equal volumes of (b) and (c) and filtering

56) Which of the following will have the highest freezing point at one atm?
a) 0.1 m NaCl solution
b) 0.1 M sugar solution
c)
d)

57) The osmotic pressure of a solution is given by the relation
a)
b)
c)
d)

58) Which is not a colligative property?
a) Osmotic pressure
b) Lowering of vapour pressure
c) Depression of freezing point
d) Elevation of boiling pont

59) Blood cells retain their normal shape in solutions which are
a) hypotonic to blood
b) isotonic to blood
c) hypertonic to blood
d) equinormal to blood

60) A semipermeable membrane is that which permits the passage of
a) Solute molecules only
b) Solvent molecules only
c) both solute and solvent molecules
d) Neither solute nor solvent molecules

61) At the same temperature which of the following solutions will be isotonic?
a) 3.42 gm of sucrose per litre of water and 0.18 gm glucose per litre of water
b) 3.42 gm of sucrose per litre and 0.18 gm glucose in 0.1 litre of water
c) 3.42 gm of sucrose per litre of water and 0.585 gm of sodium chloride per litre of water
d) 3.42 gm of sucrose per litre of water and 1.17 gm of sodium chloride per litre of water

62) The ratio of the value of any colligative property for KCI solution to that of sugar solution is nearly
a) 1
b) 0.5
c) 2
d) 2.5

63) The freezing point of 1 molal NaCl solution assuming NaCl to be 100% dissociated in water is
a)
b)
c)
d)

64) A molal solution is one that contains one mole of a solute in
a) 1000 g of the solvent
b) one litre of the solvent
c) one litre of the solution
d) 22.4 litres of the solution

65) Colligative properties of solutions are those which depend upon
a) the nature of the solvent
b) the nature of the solute
c) the number of solvent molecules
d) the number of solute particles

66) Which of the following statements is correct?
a) Lowering of vapour pressure takes place only in ideal solutions
b) Lowering of vapour pressure does not depend upon the solvent at a given concentration of the solute
c) Lowering of vapour pressure depends upon the nature of the solute
d) The relative lowering of vapour pressure does not depend upon the solvent at a given concentration of the solute

67) At constant temperature, the osmotic pressure of a solution is
a) directly proportional to the concentration
b) inversely proportional to the concentration
c) Directly proportional to the square of the concentration
d) Directly proportional to the square root of the concentration

68) The maximum freezing point is that of
a) Camphor
b) Naphthalene
c) Benzene
d) Water

69) Which inorganic precipitate acts as a semipermeable membrane?
a) Calcium phosphate
b) Nickel phosphate
c) Calcium sulphate
d) Copper ferrocyanide

70) The best and accurate method for determining osmotic pressure is
a) Negative pressure method
b) Berkeley and Hartley method
c) Morse and Frazer method
d)

71) The osmotic pressure of a solution increases if the
a) temperature is decreased
b) solution constant is increased
c) number of solute particles is increased
d) volume is increased

72) When mercuric iodide is added to the aqueous solution of potassium iodide, the
a) freezing point is raised
b) freezing point is lowered
c) freezing point does not change
d) boiling point does not change

73) A vant Hoff factor more than unity indicates that the solute in solution has
a) dissociated
b) associated
c) both
d) cannot say anything

74) Which of the following modes of expressing concentration is independent of temperature?
a) Molarity
b) Molality
c) Formality
d) Normality

75) An ideal solution is formed when its components
a) have no volume change on mixing
b) have no enthalpy change on mixing
c) have both the above characteristics
d) have high solubility

76) All form ideal solutions except
a)
b)
c)
d)

77) The vapour pressure of a solution is
a) directly proportional to the mole fraction of the solvent
b) Inversely proportional to the mole fraction of the solute
c) Inversely proportional to the mole fraction of the solvent
d) Directly proportional to the mole fraction of solute

78) In cold countries, ethylene glycol is added to water in the radiators of cars during winter. This results in
a) lowering of freezing point
b) reducing the viscosity
c) reducing the specific heat
d) making water a better conductor of electricity

79) The addition of common salt to a sample of water will
a) increase its freezing point and increase the boiling point
b) Decrease its freezing point and increase the boiling point
c) Increase both the boiling and the freezing point
d) Decrease both the boiling and the freezing point

80) Sugar is soluble in water due to
a) High solvation energy
b) Ionic character of sugar
c) High dipole moment of water
d) Hydrogen bond formation with water

81) The solubility of a gas increases in a liquid with
a) Increase of temperature
b) Reduction of gas pressure
c) Decrease in temperature
d) Amount of liquid taken

82) Which of the following 0.1 M aqueous solution will have the lowest freezing point?
a) Potassium sulphate
b) Sodium sulphate
c) Urea
d) Glucose

83) Molarity is expressed as
a) Grams/litre
b) Litres/mole
c) Moles/litre
d) Moles/1000gm

84) 100 ml of a liquid A was mixed with 25 ml of a liquid B to give a non-ideal solution of A-B mixture. The volume of this mixture will be
a) 75 ml
b) 125 ml exact
c) fluctuating between 75 ml and 125 ml
d) close to 125 ml but not exactly 125 ml

85) Which of the following is not a colligative property?
a)
b)
c)
d)

86) The relative lowering of the vapour pressure is equal to the ratio between the number of
a) solute molecules to the solvent molecules
b) solute molecules to the total molecules in the solution
c) solvent molecules to the total molecules in the solution
d) solvent molecules to the total number of ions of the solute

87) The molal depression constant depends upon the
a) nature of the solute
b) nature of the solvent
c) heat of solution of the solute in the solvent
d) vapour pressure of the solution

88) Which of the following aqueous solutions has the highest freezing point?
a) 0.1 M HCI
b) 0.05 M sucrose
c) 0.1 M glucose
d) 0.1 M NaCl

89) A non-volatile electrolyte dissolved in an aqueous solution in the same molal proportion as a non-electrolyte gives
a) the same colligative effect
b) a higher colligative effect
c) a lower colligative effect
d) no colligative effect

90) Which of the following solutions will have the highest boiling point?
a) 1% solution of glucose in water
b) 1% solution of sucrose in water
c) 1% solution of sodium chloride in water
d) 1% solution of calcium chloride in water

91) Which of the following has the minimum freezing point?
a) One molal NaCl solution
b) One molal KCI solution
c)
d) One molal urea solution

92) Which of the following aqueous solutions has minimum freezing point?
a) 0.01 m NaCl
b)
c)
d)

93) Which one is a colligative property?
a) Boiling point
b) Vapour pressure
c) Osmotic pressure
d) Freezing point

94) If 0.1 M solution of glucose and 0.1 M solution of urea are placed on two sides of the semipermeable membrane to equal heights, then it will be correct to say that
a) There will be no net movement across the membrane
b) Glucose will flow towards urea solution
c) Urea will flow towards glucose solution
d) Water will flow from urea solution to glucose solution

95) The molecular weight of sodium chloride determined by the osmotic pressure method will be
a) equal to 58.5
b) Greater than 58.5
c) Less than 58.5
d) None of the above as this method cannot be used for molecular weight determination

96) Azeotropic mixtures
a) boil at different temperatures
b) are mixtures of solids
c) are constant boiling mixtures
d) none of these

97) The pressure cooker reduces cooking time because
a) The heat is more evenly distributed
b) The high pressure tenderizes the food
c) A large flame is used
d) The boiling point of the water inside is elevated

98) The vant Hoff factor for a 0.1 M ideal solution is
a) 0.1
b) 1
c) 0.01
d) none of the tree

99) At the highest osmotic pressure is exhibited by a 0.1 M solution of
a)
b) KCI
c) Glucose
d) Urea

100) The molecular weight of a volatile liquid can be determined by the
a) Victor Meyer method
b)
c) Elevation of boiling point method
d) Depression of freezing point method


Answer :

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