Test

 TEST 2

Ashwani - 09:34

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30 Class 9 Chemistry MCQs (without answers) as requested:

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Class 9 Chemistry – 30 MCQs

1. Matter is made up of:
   a) Continuous substance
   b) Small particles
   c) Only liquids
   d) Only gases

2. The temperature at which a solid changes into a liquid is called:
   a) Boiling point
   b) Freezing point
   c) Melting point
   d) Condensation point

3. The process of conversion of water into vapour at any temperature is:
   a) Boiling
   b) Evaporation
   c) Melting
   d) Sublimation

4. Which of the following is a homogeneous mixture?
   a) Oil and water
   b) Sand and iron
   c) Salt solution
   d) Chalk and water

5. The scattering of light by colloidal particles is called:
   a) Brownian movement
   b) Tyndall effect
   c) Diffusion
   d) Evaporation

6. The SI unit of density is:
   a) g/cm³
   b) kg/m³
   c) g/mL
   d) kg/L

7. Brass is a mixture of:
   a) Copper and zinc
   b) Copper and tin
   c) Zinc and iron
   d) Copper and aluminium

8. Who proposed the law of constant proportions?
   a) Dalton
   b) Lavoisier
   c) Proust
   d) Rutherford

9. H₂O represents:
   a) 1 atom of hydrogen, 2 atoms of oxygen
   b) 1 atom of oxygen, 2 atoms of hydrogen
   c) A mixture
   d) A radical

10. The smallest particle of an element that retains its properties is:
    a) Molecule
    b) Compound
    c) Atom
    d) Ion

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Medium-Level MCQs

11. Which of the following is a pure substance?
    a) Air
    b) Soil
    c) Oxygen
    d) Milk

12. The process of converting gas into liquid is:
    a) Evaporation
    b) Condensation
    c) Fusion
    d) Sublimation

13. Which is NOT a characteristic of particles of matter?
    a) They have spaces between them
    b) They are in constant motion
    c) They attract each other
    d) They do not occupy space

14. Ice at 0°C is more effective in cooling than water at 0°C because:
    a) Ice is solid
    b) Ice has latent heat of fusion
    c) Ice is colder
    d) Water is warmer

15. A colloid is:
    a) Stable
    b) Unstable
    c) Has large particles
    d) Does not scatter light

16. The chemical formula of magnesium oxide is:
    a) MgO
    b) MgO₂
    c) Mg₂O
    d) Mg(OH)₂

17. 1 mole of any substance contains:
    a) 6.022 × 10²³ particles
    b) 3.022 × 10²³ particles
    c) 1 × 10² particles
    d) 9.022 × 10⁴ particles

18. Which of the following is an example of a compound?
    a) Brass
    b) Air
    c) Water
    d) Sand

19. The number of atoms in a molecule of ozone is:
    a) 1
    b) 2
    c) 3
    d) 4

20. Which of these will show the Tyndall effect?
    a) Salt solution
    b) Sugar solution
    c) Milk
    d) Alcohol

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Higher-Level MCQs

21. The ratio of hydrogen to oxygen in water is always 1:8 by mass. This states:
    a) Law of conservation of mass
    b) Law of constant proportions
    c) Law of multiple proportions
    d) Dalton’s law

22. Which of the following is NOT a method of separation?
    a) Filtration
    b) Sublimation
    c) Burning
    d) Chromatography

23. Brownian motion is shown by:
    a) True solution
    b) Colloids
    c) Suspensions
    d) Both b and c

24. Which property of particles increases on heating?
    a) Size
    b) Number
    c) Kinetic energy
    d) Density

25. A solution in which no more solute can dissolve at a given temperature is:
    a) Dilute
    b) Concentrated
    c) Saturated
    d) Unsaturated

26. The valency of oxygen is:
    a) 1
    b) 2
    c) 3
    d) 4

27. Isotopes of an element have:
    a) Same mass number
    b) Different atomic numbers
    c) Same atomic number but different mass numbers
    d) Same number of neutrons

28. The molecule of sulphur (S₈) is:
    a) Monoatomic
    b) Diatomic
    c) Polyatomic
    d) None

29. Which is a chemical change?
    a) Dissolving sugar in water
    b) Melting ice
    c) Burning of magnesium ribbon
    d) Breaking glass

30. Chalk powder in water is an example of:
    a) True solution
    b) Colloid
    c) Suspension
    d) Emulsion

Answer Key

1. b

2. c

3. b

4. c

5. b

6. b

7. a

8. c

9. b

10. c

11. c

12. b

13. d

14. b

15. a

16. a

17. a

18. c

19. c

20. c

21. b

22. c

23. d

24. c

25. c

26. b

27. c

28. c

29. c

30. c

Here are the answers with word explanations/details for all 30 Class 9 Chemistry MCQs.

(Each answer includes a short justification to help students understand why it is correct.)

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✅ Detailed Answer Key (with Word Explanations)

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1. b — Matter is made up of small particles

Because matter consists of tiny particles that cannot be seen by the naked eye.

2. c — Melting point

Temperature at which a solid changes into a liquid.

3. b — Evaporation

Conversion of liquid into vapour at any temperature below boiling point.

4. c — Salt solution

Salt completely dissolves in water, forming a homogeneous mixture.

5. b — Tyndall effect

Scattering of light by colloidal particles.

6. b — kg/m³

The SI unit of density is kilogram per cubic metre.

7. a — Copper and zinc

Brass is an alloy made from copper and zinc.

8. c — Proust

Proust proposed the Law of Constant Proportions.

9. b — 1 oxygen + 2 hydrogen atoms

H₂O contains 2 hydrogen atoms and 1 oxygen atom.

10. c — Atom

Smallest particle of an element that retains its chemical properties.

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11. c — Oxygen

It is a pure substance because it contains only one kind of particle.

12. b — Condensation

Gas changes to liquid on cooling.

13. d — They do not occupy space

This is false because particles of matter do occupy space.

14. b — Ice has latent heat of fusion

Ice absorbs extra heat without a rise in temperature, so it cools more effectively.

15. a — Stable

Colloids are stable mixtures and their particles do not settle down.

16. a — MgO

Magnesium oxide is formed by Mg and O combining in a 1:1 ratio.

17. a — 6.022 × 10²³ particles

This is Avogadro’s number, the definition of 1 mole.

18. c — Water

A compound made up of hydrogen and oxygen in a fixed proportion.

19. c — 3

Ozone (O₃) contains 3 atoms of oxygen.

20. c — Milk

Milk contains colloidal particles that show the Tyndall effect.

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21. b — Law of constant proportions

A chemical compound always contains elements in the same mass ratio.

22. c — Burning

Burning is not a separation method; it is a chemical change.

23. d — Both b and c

Colloids and suspensions show Brownian motion.

24. c — Kinetic energy

Particles gain kinetic energy when heated.

25. c — Saturated

A saturated solution cannot dissolve more solute at a given temperature.

26. b — 2

Oxygen gains two electrons to complete its octet; valency of O is 2.

27. c — Same atomic number, different mass numbers

This is the definition of isotopes.

28. c — Polyatomic

S₈ molecule contains many atoms (8 atoms), so it is polyatomic.

29. c — Burning of magnesium ribbon

Burning is a chemical change because new substances form.

30. c — Suspension

Chalk powder does not dissolve in water and settles down.

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