Chemistry MCQs for Class 12 with Answers Chapter 2 Solutions

MCQs Based On Class 12 Chemistry Chapter 2 Solutions

MCQ Questions for Class 12 Chemistry are prepared by the subjects experts according to the latest pattern. These MCQs are very important for students who wants to score well in CBSE Board Exam. These MCQs on Chapter 2 Solutions will also help students in understanding the concepts very well.

Q.1. Which of the following fluoride is used as rat poison?
(a) CaF₂
(b) KF
(c) NaF
(d) MgF₂

Answer

(c) Sodium fluoride is used as rat poison.

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Q.2. Vapour pressure of a pure liquid X is 2 atm at 300 K. It is lowered to 1 atm on dissolving 1 g of Y in 20 g of liquid X. If molar mass of X is 200, what is the molar mass of Y?
(a) 20
(b) 50
(c) 100
(d) 200

Answer

Answer: (b) 50

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Q.3. Most of the processes in our body occur in
(a) solid solution
(b) liquid solution
(c) gaseous solution
(d) colloidal solution

Answer

(b) Almost all the processes in our body occur in liquid solution.

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Q.4. 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) In homogeneous mixtures composition and properties both are uniform throughout the mixture.

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Q.5. 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) Mole fraction

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Q.6. Which of the following mixture is(are) called solution?
(i) water + ammonia (ii) water + acetone
(iii) acetone + alcohol (iv) hexane + water
(a) (i), (ii) and (iii) (b) (i), (iii) and (iv)
(c) (i) and (iv) (d) (ii) and (iii)

Answer

(a) Hexane is not water soluble, hence solution is not formed.

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Q.7. A plant cell shrinks when it is kept in a
(a) hypotonic solution
(b) hypertonic solution
(c) isotonic solution
(d) pure waterAnswer

Answer

(b) hypertonic solution

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Q.8. 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) solute molecules to the total number of molecules in solution

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Q.9. Which of the following is a quantitative description of the solution?
(a) Dilute
(b) Concentrated
(c) Saturated
(d) Molar

Answer

(d) Dilute, concentrated and saturated terms are qualitative methods of description of concentration of solution whereas molar or molarity is quantitative method.

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Q.10. When a solute is present in trace quantities the following expression is used
(a) Gram per million
(b) Milligram percent
(c) Microgram percent
(d) Parts per million

Answer

(d)

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Q.11. 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

Answer: (b) Henry’s law

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Q.12. Molarity of liquid HCl will be, if density of solution is 1.17 gm/cc
(a) 36.5
(b) 32.05
(c) 18.25
(d) 42.10

Answer

(b)

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Q.13. 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)

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Q.14. How much oxygen is dissolved in 100 rnL water at 298 K if partial pressure of oxygen is 0.5 atm and K = 1.4 × 10^-3 mol/L/atm?
(a) 22.4 mg
(b) 22.4 g
(c) 2.24 g
(d) 2.24 mg

Answer

Answer: (d) 2.24 mg

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Q.15. 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)

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Q.16. 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)

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Q.17. Partial pressure of a solution component is directly proportional to its mole fraction. This is known as
(a) Henry’s law
(b) Raoult’s law
(c) Distribution law
(d) Ostawald’s dilution law

Answer

Answer: (b) Raoult’s law

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Q.18. 3 moles of P and 2 moles of Q are mixed, what will be their total vapour pressure in the solution if their partial vapour pressures are 80 and 60 torr respectively?
(a) 80 torr
(b) 140 torr
(c) 72 torr
(d) 70 torr

Answer

Answer: (c) 72 torr

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Q.19. Sprinkling of salt helps in clearing the snow covered roads in hills. The phenomenon involved in the process is
(a) lowering in vapour pressure of snow
(b) depression in freezing point of snow
(c) melting of ice due to increase in temperature by putting salt
(d) increase in freezing point of snow

Answer

Answer: (b) depression in freezing point of snow

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Q.20. Which of the following solutions shows positive deviation from Raoult’s law?
(a) Acetone + Aniline
(b) Acetone + Ethanol
(c) Water + Nitric acid
(d) Chloroform + Benzene

Answer

Answer: (b) Acetone + Ethanol

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Q.21. The system that forms maximum boiling azetrope is
(a) Acetone-chloroform
(b) ethanol-acetone
(c) n-hexane-n-heptane
(d) carbon disulphide-acetone

Answer

Answer: (a) Acetone-chloroform

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Q.22. A solution containing 10.2 g glycerine per litre is isotonic with a 2% solution of glucose. What is the molecular mass of glycerine?
(a) 91.8 g
(b) 1198 g
(c) 83.9 g
(d) 890.3 g

Answer

Answer: (a) Acetone-chloroform

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Q.23. What weight of glycerol should be added to 600 g of water in order to lower its freezing point by 10°C ?
(a) 496 g
(b) 297 g
(c) 310 g
(d) 426 g

Answer

Answer: (b) 297 g

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Q.24. The osmotic pressure of a solution can be increased by
(a) increasing the volume
(b) increasing the number of solute molecules
(c) decreasing the temperature
(d) removing semipermeable membrane

Answer

Answer: (b) increasing the number of solute molecules

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Q.25. For carrying reverse osmosis for desalination of water the material used for making semipermeable membrane is
(a) potassium nitrate
(b) parchment membrane
(c) cellulose acetate
(d) cell membrane

Answer

Answer: (c) cellulose acetate

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Q.26. What will be the degree of dissociation of 0.1 M Mg(NO₃)₂ solution if van’t Hoff factor is 2.74?
(a) 75%
(b) 87%
(c) 100%
(d) 92%

Answer

Answer: (b) 87%

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Q.27. 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

Answer: (c) equal to the rate of crystallisation

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Q.28. If 2 gm of NaOH is present is 200 ml of its solution, its molarity will be
(a) 0.25
(b) 0.5
(c) 5
(d) 10

Answer

Answer: (a) 0.25

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Q.29. The atmospheric pollution is generally measured in the units of
(a) mass percentage
(b) volume percentage
(c) volume fraction
(d) ppm

Answer

Answer: (d) ppm

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Q.30. 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

Answer: (c) 68.4

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Q.31. 234.2 gm of sugar syrup contains 34.2 gm of sugar. What is the molal concentration of the solution.
(a) 0.1
(b) 0.5
(c) 5.5
(d) 55

Answer

Answer: (b) 0.5

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Q.32. 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 K_H?
(a) 0.0263 bar
(b) 69.16 bar
(c) 192 bar
(d) 282 bar

Answer

Answer: (d) 282 bar

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Q.33. 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

Answer: (b) sum of the numbers of electrons and protons of an atom

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Q.34. Henry’s law constant for molality of methane is benzene at 298 K is 4.27 × 10⁵ mm Hg. The mole fraction of methane in benzene at 298 K under 760 mm Hg is
(a) 1.78 × 10^-3
(b) 17.43
(c) 0.114
(d) 2.814

Answer

Answer: (a)

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Q.35. Among the following substances the lowest vapour pressure is exerted by
(a) water
(b) alcohol
(c) ether
(d) mercury

Answer

Answer: (d) mercury

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Q36. 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

Answer: (c)

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Q.37. 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) If added substance dissolves, the solution is unsaturated. If it does not dissolve solution is saturated. If precipitation occurs solution is supersaturated.

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Q.38. 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)

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Q.39. 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) Body temperature of human beings remains constant.

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Q.40. Value of Henry’s constant K_H _.
(a) increases with increase in temperature.
(b) decreases with increase in temperature.
(c) remains constant.
(d) first increases then decreases.

Answer

Answer: (a)

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Q.41. The value of Henry’s constant K_H 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)

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