CBSE Class 12 Chemistry Solutions MCQs Set D

Question: A 5% solution of cane-sugar (molecular weight = 342) is isotonic with 1% solution of substance A. The molecular weight of X is
(a) 342
(b) 171.2
(c) 68.4
(d) 136.8

Answer : C

Question: Out of molality (m), molarity (M), formality (F) and mole fraction (x), those which are independent of temperature are
(a) M, m
(b) F, x
(c) m, x
(d) M, x

Answer : C

Question: H₂S is a toxic gas used in qualitative analysis. If solubility of H₂S in water at STP is 0.195 m. what is the value of KH?
(a) 0.0263 bar
(b) 69.16 bar
(c) 192 bar
(d) 282 bar

Answer : D

Question: In which of the following specific condition, CO₂ gas is filled in cold drinks, and in soda water?
(a) at high temperatures and high pressure
(b) at low temperatures and high pressure
(c) at low temperatures and low pressure
(d) at high temperatures and low pressure

Answer : B

Question: Atomic mass is equal to
(a) number of electrons of an atom
(b) sum of the numbers of electrons and protons of an atom
(c) sum of the numbers of neutrons and protons of an atom
(d) none of these

Answer : B

Question: Which of the following condition is not satisfied by an ideal solution?
(a) ΔHmixing = 0
(b) ΔVmixing = 0
(c) Raoult’s Law is obeyed
(d) Formation of an azeotropic mixture

Answer : D

Question: At equillibrium 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 : C

Question: The density of a solution prepared by dissolving 120 g of urea (mol. mass = 60 u) in 1000 g of water is 1.15 g/mL. The molarity of this solution is:
(a) 2.16 M
(b) 0.50 M
(c) 1.78 M
(d) 1.02 M

Answer : A

Question: 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 : B

Question: At equilibrium the rate of dissociation 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 : C

Question: 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 : B

Question: Mole fraction of glycerine C₃H₅(OH)₃ in solution containing 36 g of water and 46 g of glycerine is
(a) 0.46
(b) 0.40
(c) 0.20
(d) 0.36

Answer : C

Question: 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 : B

Question: The term homogenous mixtures signifies that
(a) its composition is uniform throughout the mixture.
(b) its properties are uniform throughout the mixture.
(c) both composition and properties are uniform throughout the mixture.
(d) neither composition nor properties are uniform throughout the mixture.

Answer : C

Question: The relative lowering in vapour pressure is proportional to the ratio of number of
(a) solute molecules to solvent molecules
(b) solvent molecules to solute molecules
(c) solute molecules to the total number of molecules in solution
(d) solvent molecules to the total number of molecules in solutionAnswer

Answer : C

Question: Which of the following statements is incorrect?
(a) German silver contains Cu, Zn, and Ni.
(b) Bronze is a mixture of Cu and Sn.
(c) Brass is a mixture of Cu and Zn.
(d) Solutions are heterogeneous mixtures of two or more than two components.

Answer : D

Question: People add sodium chloride to water while boiling eggs. This is to
(a) decrease the boiling point.
(b) increase the boiling point.
(c) prevent the breaking of eggs.
(d) make eggs tasty.

Answer : B

Question: 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 : A

Question: What is the percentage of solute in the resultant solution, if is obtained by mixing 300 g of 30% and 200 g of 20% solution by weight?
(a) 50%
(b) 26%
(c) 62%
(d) 32%

Answer : B

Question: 2.82 g of glucose (molar mass = 180) is dissolved in 30 g of water. Calculate the molality
(a) 3.5 m
(b) 1.8 m
(c) 0.955 m
(d) 0.522 m

Answer : D

Question: Which of the following is a quantitative description of the solution?
(a) Dilute
(b) Concentrated
(c) Saturated
(d) Molar

Answer : D

Question: The law which indicates the relation’-hip between solubility of a gas in liquid and pressure rs
(a) Raoult’s law
(b) Henry’s law
(c) Lowering of vapour pressure
(d) Van’t Hoff lawAnswer

Answer : B

Question: Which law explained solubility of gases in a liquid?
(a) Charles' law
(b) Henry's law
(c) Raoult's law
(d) Boyle's law

Answer : B

Question: 1 M, 2.5 litre NaOH solution is mixed with another 0.5 M, 3 litre NaOH solution. Then find out the molarity of resultant solution
(a) 0.80 M
(b) 1.0 M
(c) 0.73 M
(d) 0.50 M

Answer : C

Question: An X molal solution of a compound in benzene has mole fraction of solute equal to 0.2. The value of X is
(a) 14
(b) 3.2
(c) 1.4
(d) 2

Answer : B

Question: On which factors, the solubility of the gaseous solute in a liquid depends?
(a) Temperature
(b) Pressure of the gas
(c) Nature of gaseous solute and solvent
(d) All of these

Answer : D

Question: Fishes feel uncomfortable in warm water due to:
(a) fishes do not like warmness
(b) higher amount of impurities
(c) low solubility of oxygen at higher temperature
(d) greater population of fishes

Answer : A

Question: The molarity of the solution containing 7.1 g of Na₂SO₄ in 100 ml of aqueous solution is
(a) 2 M
(b) 0.5 M
(c) 1 M
(d) 0.05 M

Answer : B

Question: The Solubility of gas in a liquid increase with:
(a) Increases of temperature
(b) Amount of liquid taken
(c) Decrease in temperature
(d) Reduction of gas pressure pressure, the freezing point of water decreases.

Answer : C

Question: In which condition, Henry's law is applicable?
(a) Ideal behaviour of gaseous solute at high pressure and low temperature
(b) Gaseous solute neither associate nor dissociate in solution
(c) Gaseous solute react with solvent
(d) Applicable in given all conditions

Answer : A

Question: Which of the following fluoride is used as rat poison?
(a) CaF₂
(b) KF
(c) NaF
(d) MgF₂

Answer : C

Question: A plant cell shrinks when it is kept in a
(a) hypotonic solution
(b) hypertonic solution
(c) isotonic solution
(d) pure waterAnswer

Answer : B