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Solutions Class 12 MCQs Questions with Answers
Solve this Solutions Multiple Choice Questions of Class 12 Chemistry Chapter 2 MCQ, so as not to miss out on any concept from being clear about what they mean!
Question 1.
Which of the following units is useful in relating concentration of solution with its vapour pressure?
(a) mole fraction
(b) parts per million
(c) mass percentage
(d) molality
Answer
Answer: (a) mole fraction
Question 2.
On dissolving sugar in water at room temperature, solution feels cool to touch. Under which of the following cases dissolution of sugar will be most rapid?
(a) Sugar crystals in cold water.
(b) Sugar crystals in hot water.
(c) Powdered sugar in cold water.
(d) Powdered sugar in hot water.
Answer
Answer: (d) Powdered sugar in hot water.
Question 3.
At equilibrium the rate of dissolution of a solid solute in a volatile liquid solvent is ………….
(a) less than the rate of crystallisation
(b) greater than the rate of crystallisation
(c) equal to the rate of crystallisation
(d) zero
Answer
Answer: (c) equal to the rate of crystallisation
Question 4.
A beaker contains a solution of substance ‘A’. Precipitation of substance ‘A’ takes place when small amount of ‘A’ is added to the solution. The solution is ………………
(a) saturated
(b) supersaturated
(c) unsaturated
(d) concentrated
Answer
Answer: (b) supersaturated
Question 5.
Maximum amount of a solid solute that can be dissolved in a specified amount of a given liquid solvent does not depend upon .
(a) temperature
(b) nature of solute
(c) pressure
(d) nature of solvent
Answer
Answer: (c) pressure
Question 6.
Low concentration of oxygen in the blood and tissues of people living at high altitude is due to
(a) low temperature
(b) low atmospheric pressure
(c) high atmospheric pressure
(d) both low temperature and high atmospheric pressure
Answer
Answer: (b) low atmospheric pressure
Question 7.
Considering the formation, breaking and strength of hydrogen bond, predict which of the following mixtures will show a positive deviation from Raoult’s law?
(a) Methanol and acetone.
(b) Chloroform and acetone.
(c) Nitric acid and water.
(d) Phenol and aniline.
Answer
Answer: (a) Methanol and acetone.
Question 8.
Colligative properties depend on
(a) the nature of the solute particles dissolved in solution.
(b) the number of solute particles in solution.
(c) the physical properties of the solute particles dissolved in solution.
(d) the nature of solvent particles.
Answer
Answer: (b) the number of solute particles in solution.
Question 9.
Which of the following aqueous solutions should have the highest boiling point?
(o) 1.0 M NaOH
(b) 1.0 M Na2SO4
(c) 1.0 M NH4NO3
(d) 1.0 M KNO3
Answer
Answer: (b) 1.0 M Na2SO4
Question 10.
The unit of ebullioscopic constant is
(a) K kg mol-1 or K (molality)-1
(b) mol kg K-1 or K-1 (molality)
(c) kg mol-1 K-1 or K-1 (molality)-1
(d) K mol kg-1 or K (molality)
Answer
Answer: (a) K kg mol-1 or K (molality)-1
Question 11.
In comparison to a 0.01 M solution of glucose, the depression in freezing point of a 0.01 M MgCl2 solution is ………..
(a) the same
(b) about twice
(c) about three times
(d) about six times
Answer
Answer: (c) about three times
Question 12.
An unripe mango placed in a concentrated salt solution to prepare pickle shrivels because ………..
(a) it gains water due to osmosis.
(b) it loses water due to reverse osmosis.
(c) it gains water due to reverse osmosis.
(d) it loses water due to osmosis.
Answer
Answer: (d) it loses water due to osmosis.
Question 13.
At a given temperature, osmotic pressure of a concentrated solution of a substance
(a) is higher than that of a dilute solution.
(b) is lower than that of a dilute solution.
(c) is same as that of a dilute solution.
(d) cannot be compared with osmotic pressure of dilute solution.
Answer
Answer: (a) is higher than that of a dilute solution.
Question 14.
Which of the following statements is false?
(a) Two different solutions of sucrose of same molality prepared in different solvents will have the same depression in freezing point.
(b) The osmotic pressure of a solution is given by the equation π = cRT (where c is the molarity of the solution).
(c) Decreasing order of osmotic pressure for 0.01 M aqueous solutions of barium chloride, potassium chloride, acetic acid and sucrose is BaCl2 > KCl > CH3COOH > sucrose.
(d) According to Raoult’s law, the vapour pressure exerted by a volatile component of a solution is directly proportional to its mole fraction in the solution.
Answer
Answer: (a) Two different solutions of sucrose of same molality prepared in different solvents will have the same depression in freezing point.
Question 15.
The values of Van’t Hoff factors for KCl, NaCl and K2SO4, respectively, are
(a) 2, 2 and 2
(b) 2, 2 and 3
(c) 1,1 and 2
(d) 1, 1 and 1
Answer
Answer: (b) 2, 2 and 3
Question 16.
Which of the following statements is false?
(a) Units of atmospheric pressure and osmotic pressure are the same.
(b) In reverse osmosis, solvent molecules move through a semipermeable membrane from a region of lower concentration of solute to a region of higher concentration.
(c) The value of molal depression constant depends on nature of solvent.
(d) Relative lowering of vapour pressure is a dimensionless quantity.
Answer
Answer: (b) In reverse osmosis, solvent molecules move through a semipermeable membrane from a region of lower concentration of solute to a region of higher concentration.
Question 17.
Value of Henry’s constant, KH
(a) increases with increase in temperature.
(b) decreases with increase in temperature.
(c) remains constant.
(d) first increases then decreases.
Answer
Answer: (a) increases with increase in temperature.
Question 18.
The value of Henry’s constant KH is
(a) greater for gases with higher solubility.
(b) greater for gases with lower solubility.
(c) constant for all gases.
(d) not related to the solubility of gases.
Answer
Answer: (b) greater for gases with lower solubility.
Question 19.
Consider the figure given below and mark the correct option.
(a) Water will move from side (A) to side (B) if a pressure lower than osmotic pressure is applied on piston (B).
(b) Water will move from side (B) to side (A) if a pressure greater than osmotic pressure is applied on piston (B).
(c) Water will move from side (B) to side (A) if a pressure equal to osmotic pressure is applied on piston (B).
(d) Water will move from side (A) to side (B) if pressure equal to osmotic pressure is applied on piston (A).
Answer
Answer: (b) Water will move from side (B) to side (A) if a pressure greater than osmotic pressure is applied on piston (B).
Question 20.
We have three aqueous solutions of NaCl labelled as ‘A’, ‘B’ and ‘C’ with concentrations 0.1 M, 0.01 M and 0.001 M, respectively. The value of van’t Hoff factor for these solutions will be in the order
(a) iA < iB < iC
(b) iA > iB > iC
(c) iA = iB = iC
(d) iA < iB > iC
Answer
Answer: (c) iA = iB = iC
Question 21.
On the basis of information given below mark the correct option.
Information:
(A) In bromoethane and chloroethane mixture, intermolecular interactions of A-A and B-B types are nearly same as A-B type interactions.
(B) In ethanol and acetone mixture, A-A or B-B type intermolecular interactions are stronger than A-B
type interactions.
(C) In chloroform and acetone mixture, A-A or B-B type intermolecular interactions are weaker than A-B type interactions.
(a) Solutions (B) and (C) will follow Raoult’s law.
(b) Solution (A) will follow Raoult’s law.
(c) Solution (B) will show negative deviation from Raoult’s law.
(d) Solution (C) will show positive deviation from Raoult’s law.
Answer
Answer: (b) Solution (A) will follow Raoult’s law.
Question 22.
Two beakers of capacity 500 mL were taken. One of these beakers, labelled as “A”, was filled with 400 mL water whereas the beaker labelled “B” was filled with 400 mL of 2 M solution of NaCl. At the same temperature both the beakers were placed in closed containers of same material and same capacity as shown in the figure given below:
At a given temperature, which of the following statements is correct about the vapour pressure of pure water and that of NaCl solution?
(a) Vapour pressure in container (A) is more than that in container (B).
(b) Vapour pressure in container (A) is less than that in container (B).
(c) Vapour pressure is equal in both the containers.
(d) Vapour pressure in container (B) is twice the vapour pressure in container (A).
Answer
Answer: (a) Vapour pressure in container (A) is more than that in container (B).
Question 23.
If two liquids A and B form minimum boiling azeotrope at some specific composition, then .
(a) A-B interactions are stronger than those between A-A or B-B.
(b) Vapour pressure of solution increases because more number of molecules of liquids A and B can escape from the solution.
(c) Vapour pressure of solution decreases because less number of molecules of only one of the liquids escape from the solution.
(d) A-B interactions are weaker than those between A-A or B-B.
Answer
Answer: (d) A-B interactions are weaker than those between A-A or B-B.
Question 24.
4 L of 0.02 M aqueous solution of NaCl was diluted by adding one litre of water. The molality of the resultant solution is
(a) 0.004
(b) 0.008
(c) 0.012
(d) 0.016
Answer
Answer: (d) 0.016
Question 25.
On the basis of information given below mark the correct option.
Information: On adding acetone to methanol some of the hydrogen bonds between methanol molecules break.
(a) At specific composition, methanol- acetone mixture will form minimum boiling azeotrope and will show positive deviation from Raoult’s law.
(b) At specific composition, methanol- acetone mixture forms maximum boiling azeotrope and will show positive deviation from Raoult’s law.
(c) At specific composition, methanol- acetone mixture will form minimum boiling azeotrope and will show negative deviation from Raoult’s law.
(d) At specific composition, methanol- acetone mixture will form maximum boiling azeotrope and will show
negative deviation from Raoult’s law.
Answer
Answer: (a) At specific composition, methanol- acetone mixture will form minimum boiling azeotrope and will show positive deviation from Raoult’s law.
Question 26.
KH value for Ar(g), CO2(g), HCHO (g) and CH4(g) are 40.39, 1.67, 1.83 × 10-5 and 0.413 respectively.
Arrange these gases in the order of their increasing solubility.
(a) HCHO < CH4 < CO2 < Ar
(b) HCHO < CO2 < CH4 < Ar
(c) Ar < CO2 < CH4 < HCHO
(d) Ar < CH4 < CO2 < HCHO
Answer
Answer: (c) Ar < CO2 < CH4 < HCHO
Assertion and Reason Type Questions
The questions given below consist of an assertion and a reason. Use the following key to choose the appropriate answer.
(a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).
(b) Both Assertion (A) and Reason (R) are correct statements, but Reason (R) is not the correct explanation of the Assertion (A).
(c) Assertion (A) is correct, Reason (R) is wrong statement.
(d) Assertion (A) is wrong, but Reason (R) is correct statement.
Question 27.
Assertion: ΔHmix and ΔVmix are zero for the ideal solution.
Reason: The interactions between the particles of the components of a solution are almost identical as between particles in the liquids.
Answer
Answer: (a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).
Question 28.
Assertion: Increasing pressure on water decreases its freezing point.
Reason: Density of water is maximum at 273 K.
Answer
Answer: (c) Assertion (A) is correct, Reason (R) is wrong statement.
Question 29.
Assertion: 0.1 M glucose solution has higher increment in the freezing point than 0.1 M urea solution.
Reason: Kf for both has same values.
Answer
Answer: (d) Assertion (A) is wrong, but Reason (R) is correct statement.
Question 30.
Assertion: Cooking time in pressure cookers is reduced.
Reason: Boiling point inside the pressure cooker is raised.
Answer
Answer: (a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).
Question 31.
Assertion: The sum of mole fractions of all components of a solution is unity.
Reason: Mole fraction is independent of temperature.
Answer
Answer: (b) Both Assertion (A) and Reason (R) are correct statements, but Reason (R) is not the correct explanation of the Assertion (A).
Question 32.
Assertion: Sodium chloride is used to clear snow on the roads.
Reason: Sodium chloride depresses the freezing point of water.
Answer
Answer: (a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).
Question 33.
Assertion: Osmotic pressure of 0.1 M urea solution is less than that of 0.1 M NaCl solution.
Reason: Osmotic pressure is not a colligative property.
Answer
Answer: (c) Assertion (A) is correct, Reason (R) is wrong statement.
Question 34.
Assertion: Elevation in boiling point for two isotonic solutions may not be same.
Reason: Boiling point depends upon the concentration of the solute.
Answer
Answer: (c) Assertion (A) is correct, Reason (R) is wrong statement.
Question 35.
Assertion: Iodine is more soluble in CCl4 than in water.
Reason: Non-polar solutes are more soluble in non-polar solvents.
Answer
Answer: (a) Both Assertion (A) and Reason (R) are correct statements, and Reason (R) is the correct explanation of the Assertion (A).
Question 36.
Assertion: Camphor is usually used in molecular mass determination.
Reason: Camphor has low cryoscopic constant and therefore, causes greater depression in freezing point.
Answer
Answer: (c) Assertion (A) is correct, Reason (R) is wrong statement.
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