Here are important multiple choice questions from CBSE Class 9 Science Chapter 2.

1. …………………….. are constituted by more than one kind of pure component.

a) mixtures

b) matter

c) atoms

d) substances

Answer: mixtures

2. A substance cannot be changed into other kinds of matter by any ………………………….. process.

a) chemical

b) physical

c) electrochemical

d) None of these

Answer: physical

3. Which of the following is an example of a pure substance?

a) sugar

b) milk

c) soil

d) Juice

Answer: sugar

4. A mixture contains …………………………… substance.

a) one

b) two

c) three

d) more than one

Answer: more than one

5. Mixtures that have a uniform composition throughout are called ……………………………

a) homogeneous mixtures

b) heterogeneous mixtures

c) indigenous mixtures

d) None of these

Answer: homogeneous mixtures

6. Mixtures which have non-uniform compositions and physically different parts are called …………………………

a) homogeneous mixtures

b) heterogeneous mixtures

c) indigenous mixtures

d) None of these

Answer: heterogeneous mixtures

7. Sugar dissolved in water is an example of a …………………………………..

a) homogeneous mixture

b) heterogeneous mixture

c) indigenous mixture

d) None of these

Answer: homogeneous mixture

8. A mixture of oil and water is an example of a ………………………………….

a) homogeneous mixture

b) heterogeneous mixture

c) immiscible solution

d) heterogeneous immiscible solution

Answer: heterogeneous immiscible solution

9. When you add chalk powder or wheat flour to water, you get a ……………………………..

a) solution

b) suspension

c) colloidal solution

d) None of these

Answer: suspension

10. When you add a few drops of milk or ink to water, you get a ………………………………..

a) solution

b) suspension

c) colloidal solution

d) All of the above

Answer: colloidal solution

11. ……………………….. is a pure single form of matter.

a) substance

b) solution

c) mixture

d) All of these

Answer: substance

12. A ………………………….. is a homogeneous mixture of two or more substances.

a) solution

b) colloidal solution

c) suspension

d) None of these

Answer: solution

13. Alloys are …………………………………

a) solid solutions

b) colloidal solutions

c) gaseous solutions

d) None of these

Answer: solid solutions

14. ………………………………. are mixtures of two or more metals and a metal or non-metal.

a) alloys

b) metalloids

c) semiconductors

d) None of these

Answer: alloys

15. Brass is an alloy of ……………………. and ………………………

a) silver and copper

b) copper and zinc

c) copper and iron

d) zinc and iron

Answer: copper and zinc

16. Name the components of a solution.

a) solvent and solute

b) solvent and catalyst

c) catalyst and solute

d) None of these

Answer: solvent and solute

17. The component that is dissolved in the solvent is the ………………………………

a) solute

b) solution

c) catalyst

d) None of these

Answer: solute

18. The component that dissolves the other component in a solution is the ………………………………..

a) solute

b) solution

c) solvent

d) catalyst

Answer: solvent

19. Tincture of iodine is a solution of …………………………….

a) iodine and alcohol

d) iodine and oil

c) iodine and water

d) iodine and spirit

Answer: iodine and alcohol

20. Name the solute and solvent in soda water

a) oxygen and water

b) water and carbon dioxide

c) carbon dioxide and water

d) carbon and water

Answer: carbon dioxide and water

21. Which is the main constituent of air?

a) oxygen

b) carbon

c) nitrogen

d) hydrogen

Answer: nitrogen

22. When no more solute can be dissolved in a solution at a given temperature, it is called a ………………………………

a) dilute solution

b) concentrated solution

c) saturated solution

d) None of these

Answer: saturated solution

23. The amount of solute present in the saturated solution at a given temperature is its ………………………………..

a) solvency

b) solubility

c) solvent

d) None of these

Answer: solubility

24. A solution contains 50 gram of common salt in 350 gram of water. Calculate the concentration in terms of mass by mass percentage of the solution.

a) 1.25%

b) 12.5%

c) 10%

d) 11.5%

Answer: 12.5% ((50/400) x 100 = 12.5%)

25. Non-homogeneous solutions in which solids are dispersed in liquids are called ……………………………

a) saturated solution

b) colloidal solution

c) suspension

d) non saturated solution

Answer: suspension

26. Particles of a ………………………….. are visible to the naked eye.

a) solution

b) suspension

c) saturated solution

d) None of these

Answer: suspension

27. A colloid is a ……………………………… mixture.

a) homogenous

b) heterogenous

c) Neither of these

Answer: heterogeneous

28. The scattering of a beam of light by a colloidal solution is called………………………….

a) Raman effect

b) Hawking effect

c) Tyndall effect

d) None of these

Answer: Tyndall effect

29. Which technique can be used to separate the particles of a colloidal solution?

a) filtration

b) boiling

c) evaporation

d) centrifugation

Answer: centrifugation

30. Which method is used to separate dye from ink?

a) filtration

b) evaporation

c) centrifugation

d) sieving

Answer: evaporation

31. Which method is used to separate cream from milk?

a) evaporation

b) centrifugation

c) filtration

d) None of these

Answer: centrifugation

32. Which method of separation is used in diagnostic laboratories for blood and urine tests?

a) centrifugation

b) filtration

c) handpicking

d) evaporation

Answer: centrifugation

33. When a liquid is spun rapidly, the denser particles are pushed to the bottom and the lighter particles stay at the top. This method of separation is called …………………………

a) centrifugation

b) filtration

c) handpicking

d) evaporation

Answer: centrifugation

34. When we add oil to water, they do not mix and form two separate layers. Such liquids are called

a) miscible liquids

b) immiscible liquids

c) saturated liquids

d) unsaturated liquids

Answer: immiscible liquids

35. Which of the following is an example of solids which sublime when kept in an open container?

a) camphor

b) sodium chloride

c) potassium permanganate

d) calcium carbonate

Answer: camphor

36. Pick the odd one out.

a) naphthalene

b) camphor

c) ammonium chloride

d) sodium bicarbonate

Answer: sodium bicarbonate (All the other three substances sublime.)

37. Which method is used to separate salt and ammonium chloride?

a) centrifugation

b) sublimation

c) filtration

d) None of these

Answer: sublimation

38. Which method is used to separate drugs from blood?

a) sublimation

b) chromatography

c) oxidation

d) filtration

Answer: chromatography

39. Which method is used to separate a mixture of two miscible liquids?

a) sublimation

b) distillation

c) centrifugation

d) None of these

Answer: distillation

40. Which method of separation is used for separating a mixture of two or more miscible liquids for which the difference in boiling points is less than 25K?

a) distillation

b) fractional distillation

c) sublimation

d) evaporation

Answer: fractional distillation

41. Which method is used to separate different gases from air?

a) distillation

b) fractional distillation

c) sublimation

d) evaporation

Answer: fractional distillation

42. Which method is used to purify solids?

a) distillation

b) fractional distillation

c) sublimation

d) crystallisation

Answer: crystallisation

43. Which method is used to separate a mixture containing kerosene and petrol which are miscible with each other?

a) distillation

b) fractional distillation

c) sublimation

d) evaporation

Answer: distillation

44. Name the technique used to separate camphor from salt?

a) distillation

b) fractional distillation

c) sublimation

d) evaporation

Answer: sublimation

45. What is the basic form of matter that cannot be broken down into simpler substances by chemical reactions?

a) compound

b) element

c) substance

d) None of these

Answer: element

46. Which is the only metal that exists in liquid form at room temperature?

a) argon

b) mercury

c) calcium

d) phosphorus

Answer: mercury

47. Which of the following is an example of a metalloid?

a) iodine

b) silicon

c) bromine

d) chlorine

Answer: silicon

48. Pick the odd one out.

a) boron

b) silicon

c) germanium

d) carbon

Answer: carbon (Carbon is a non-metal; the other three are metalloids.)

49. Name the two elements which are liquids at room temperature

a) boron and silicon

b) germanium and mercury

c) mercury and bromine

d) bromine and argon

Answer: mercury and bromine

50. The constituents of a compound can be separated only by ………………………….

a) physical changes

b) chemical changes

c) physical and chemical changes

d) chemical and electrochemical changes

Answer: chemical and electrochemical changes

51. When elements just mix together, they form …………………………………

a) a mixture

b) a compound

c) an alloy

d) a metalloid

Answer: mixture

52. When elements react with one another, they form …………………………..

a) mixtures

b) compounds

c) solutions

d) None of these

Answer: compounds

53. Which is a colourless gas that smells like rotten eggs?

a) hydrogen

b) carbon monoxide

c) hydrogen sulphide

d) bromine

Answer: hydrogen sulphide

54. Pure substances can be …………………………..

a) elements

b) compounds

c) mixtures

d) elements or compounds

Answer: elements or compounds