NCERT Class 9 Science MCQ | Chapter 5: Exploring Mixtures and Their Separation
Q1. A mixture in which the composition is uniform throughout is called:
(A) Heterogeneous mixture
(B) Homogeneous mixture
(C) Suspension
(D) Colloid
Answer: (B) Homogeneous mixture
Q2. Which of the following is an example of a homogeneous mixture?
(A) Sand and water
(B) Oil and water
(C) Sugar and water
(D) Muddy water
Answer: (C) Sugar and water
Q3. Which of the following is a heterogeneous mixture?
(A) Vinegar
(B) Soda
(C) Sugar solution
(D) Sand and water
Answer: (D) Sand and water
Q4. In a sugar solution, sugar acts as the:
(A) Solvent
(B) Solute
(C) Suspension
(D) Dispersion medium
Answer: (B) Solute
Q5. In a sugar solution, water acts as the:
(A) Solute
(B) Dispersed phase
(C) Solvent
(D) Coagulant
Answer: (C) Solvent
Q6. The amount of solute dissolved in a given amount of solvent or solution is called:
(A) Solubility
(B) Concentration
(C) Density
(D) Saturation
Answer: (B) Concentration
Q7. Which percentage expresses the number of grams of solute present in 100 g of solution?
(A) Mass by mass percentage
(B) Mass by volume percentage
(C) Volume by volume percentage
(D) Volume by mass percentage
Answer: (A) Mass by mass percentage
Q8. A solution contains 10 g of salt dissolved in 90 g of water. What is its mass by mass percentage?
(A) 5%
(B) 9%
(C) 10%
(D) 11%
Answer: (C) 10%
Q9. A 5% m/v glucose solution contains:
(A) 5 g glucose in 100 g solution
(B) 5 g glucose in 100 mL solution
(C) 5 mL glucose in 100 mL solution
(D) 5 g glucose in 5 mL solution
Answer: (B) 5 g glucose in 100 mL solution
Q10. Volume by volume percentage is particularly useful when:
(A) A solid is dissolved in a liquid
(B) Two miscible liquids are mixed
(C) Two solids are mixed
(D) A solid is suspended in a liquid
Answer: (B) Two miscible liquids are mixed
Q11. A pesticide spray contains 1 mL pesticide in 100 mL of solution. Its volume by volume percentage is:
(A) 0.1%
(B) 1%
(C) 10%
(D) 100%
Answer: (B) 1%
Q12. The maximum amount of solute that dissolves in a fixed quantity of solvent at a given temperature is called:
(A) Concentration
(B) Solubility
(C) Saturation
(D) Crystallization
Answer: (B) Solubility
Q13. A solution that cannot dissolve any more solute at a particular temperature is called:
(A) Dilute solution
(B) Unsaturated solution
(C) Saturated solution
(D) Colloidal solution
Answer: (C) Saturated solution
Q14. The solubility of most solid solutes in liquids generally:
(A) Decreases with increase in temperature
(B) Increases with increase in temperature
(C) Remains unchanged with temperature
(D) Becomes zero at high temperature
Answer: (B) Increases with increase in temperature
Q15. The solubility of gases in liquids generally:
(A) Increases with increase in temperature
(B) Decreases with increase in temperature
(C) Remains constant
(D) First becomes zero and then increases
Answer: (B) Decreases with increase in temperature
Q16. A graph showing solubility of a substance against temperature is called:
(A) Heating curve
(B) Cooling curve
(C) Solubility curve
(D) Concentration curve
Answer: (C) Solubility curve
Q17. The solubility of compound B at 60°C is 287 g per 100 g of water, while at 40°C it is 241 g per 100 g of water. How much compound B separates out when the saturated solution is cooled from 60°C to 40°C?
(A) 36 g
(B) 46 g
(C) 48 g
(D) 54 g
Answer: (B) 46 g
Q18. The process of forming crystals from a saturated solution is called:
(A) Distillation
(B) Filtration
(C) Crystallization
(D) Sublimation
Answer: (C) Crystallization
Q19. Crystallization is mainly based on differences in:
(A) Density at different temperatures
(B) Solubility at different temperatures
(C) Colour at different temperatures
(D) Boiling point at different temperatures
Answer: (B) Solubility at different temperatures
Q20. Slow cooling of a saturated solution generally helps in the formation of:
(A) Smaller and irregular crystals
(B) Larger and well-shaped crystals
(C) Gas bubbles
(D) Colloidal particles
Answer: (B) Larger and well-shaped crystals
Q21. Which of the following can be obtained naturally as crystals?
(A) Sugar crystals
(B) Snowflakes
(C) Rock salt
(D) All of the above
Answer: (D) All of the above
Q22. Distillation can be used to separate two miscible liquids when their boiling points differ by:
(A) At least about 5°C
(B) At least about 10°C
(C) At least about 25°C
(D) Exactly 100°C
Answer: (C) At least about 25°C
Q23. During distillation, the liquid having the lower boiling point:
(A) Freezes first
(B) Vaporises first
(C) Condenses first without heating
(D) Remains permanently in the flask
Answer: (B) Vaporises first
Q24. In a distillation apparatus, the vapour is converted back into liquid by:
(A) Evaporation
(B) Filtration
(C) Condensation
(D) Sublimation
Answer: (C) Condensation
Q25. Acetone and water can be separated by distillation because their boiling points are approximately:
(A) 56°C and 100°C
(B) 78°C and 100°C
(C) 61°C and 80°C
(D) 40°C and 60°C
Answer: (A) 56°C and 100°C
Q26. Fractional distillation is used for separating components having:
(A) Very large differences in boiling points
(B) Relatively small differences in boiling points
(C) Equal boiling points only
(D) No difference in physical properties
Answer: (B) Relatively small differences in boiling points
Q27. Crude petroleum is separated into different useful fractions mainly by:
(A) Filtration
(B) Crystallization
(C) Fractional distillation
(D) Sublimation
Answer: (C) Fractional distillation
Q28. Paper chromatography separates components of a mixture mainly because they:
(A) Have different colours only
(B) Move at different rates on the paper
(C) Have identical solubilities
(D) Have the same interaction with the paper
Answer: (B) Move at different rates on the paper
Q29. In paper chromatography, the solvent level at the beginning should be:
(A) Above the sample spot
(B) At the top of the paper
(C) Below the sample spot
(D) Equal to the height of the paper
Answer: (C) Below the sample spot
Q30. Which of the following can be separated using paper chromatography?
(A) Pigments in flower petals
(B) Sand and stones
(C) Oil and water
(D) Iron filings and sulphur
Answer: (A) Pigments in flower petals
Q31. Oil and water are called immiscible liquids because they:
(A) Have the same density
(B) Mix completely
(C) Do not mix with each other
(D) Have the same boiling point
Answer: (C) Do not mix with each other
Q32. Which apparatus is used to separate two immiscible liquids?
(A) Separating funnel
(B) Distillation flask
(C) Evaporating dish
(D) Chromatography paper
Answer: (A) Separating funnel
Q33. In a mixture of mustard oil and water, the mustard oil forms the upper layer because it:
(A) Is denser than water
(B) Is less dense than water
(C) Has a higher boiling point
(D) Is soluble in water
Answer: (B) Is less dense than water
Q34. Most mixtures of gases are generally:
(A) Heterogeneous
(B) Homogeneous
(C) Suspensions
(D) Colloids
Answer: (B) Homogeneous
Q35. Which of the following is a heterogeneous mixture containing a gas as one of its components?
(A) Hydrogen and oxygen
(B) Smoke
(C) Sugar solution
(D) Vinegar
Answer: (B) Smoke
Q36. Sublimation is the process in which a solid changes directly into:
(A) Liquid
(B) Gas or vapour
(C) Plasma
(D) Solution
Answer: (B) Gas or vapour
Q37. Which mixture can be separated by sublimation?
(A) Camphor and sand
(B) Salt and water
(C) Oil and water
(D) Sugar and water
Answer: (A) Camphor and sand
Q38. During the separation of camphor and sand by sublimation, camphor:
(A) Remains in the china dish
(B) Changes directly from solid to vapour
(C) Dissolves in water
(D) Settles at the bottom
Answer: (B) Changes directly from solid to vapour
Q39. The reverse process of sublimation, in which vapour changes directly into a solid, is called:
(A) Evaporation
(B) Condensation
(C) Deposition
(D) Distillation
Answer: (C) Deposition
Q40. A suspension contains particles that are:
(A) Smaller than solution particles
(B) Invisible to the naked eye
(C) Large enough to be visible to the naked eye
(D) Always less than 1 nm in diameter
Answer: (C) Large enough to be visible to the naked eye
Q41. Which of the following is an example of a suspension?
(A) Salt solution
(B) Sugar solution
(C) Sand in water
(D) Vinegar
Answer: (C) Sand in water
Q42. The particles of a suspension generally:
(A) Remain permanently dissolved
(B) Settle down when left undisturbed
(C) Cannot be seen
(D) Always show no movement
Answer: (B) Settle down when left undisturbed
Q43. Centrifugation separates components of a mixture mainly by:
(A) Rapid spinning
(B) Heating
(C) Freezing
(D) Chromatography
Answer: (A) Rapid spinning
Q44. During centrifugation, the heavier particles generally:
(A) Move outward and settle at the bottom of the tube
(B) Remain at the top
(C) Evaporate
(D) Dissolve completely
Answer: (A) Move outward and settle at the bottom of the tube
Q45. Centrifugation can be used in laboratories to separate:
(A) Red blood cells and plasma
(B) Sugar and water
(C) Oil and water
(D) Salt and sand
Answer: (A) Red blood cells and plasma
Q46. Assertion (A): Solutions do not show the Tyndall effect.
Reason (R): The particles in a solution are extremely small and do not scatter light sufficiently to make the path of light visible.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Q47. Assertion (A): Milk can show the Tyndall effect.
Reason (R): Milk is a colloid containing particles that can scatter light.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Q48. Assertion (A): Blood is considered a colloid.
Reason (R): The particles in a colloid are larger than those in a true solution but smaller than those in a suspension.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Q49. Assertion (A): Alum can help in cleaning muddy water.
Reason (R): Alum causes fine suspended particles to clump together so that they can settle and be separated.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
Q50. Assertion (A): Distillation can be used to separate acetone and water.
Reason (R): Acetone and water have sufficiently different boiling points, about 56°C and 100°C respectively.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A) Both A and R are true, and R is the correct explanation of A.
NCERT Class 9 Science MCQ | Chapter 5: Exploring Mixtures and Their Separation
Assertion Reason Type Question
Q1. Assertion (A): A homogeneous mixture has a uniform composition throughout.
Reason (R): The components of a homogeneous mixture are uniformly distributed.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A)
Q2. Assertion (A): A suspension can be separated by filtration.
Reason (R): The particles of a suspension are large enough to be retained by filter paper.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A)
Q3. Assertion (A): A solution does not show the Tyndall effect.
Reason (R): The particles of a solution are extremely small and do not scatter light sufficiently to make its path visible.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A)
Q4. Assertion (A): Oil and water can be separated using a separating funnel.
Reason (R): Oil and water are immiscible liquids and form separate layers due to their different densities.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A)
Q5. Assertion (A): Acetone and water can be separated by distillation.
Reason (R): Acetone and water have different boiling points, approximately 56°C and 100°C respectively.
(A) Both A and R are true, and R is the correct explanation of A.
(B) Both A and R are true, but R is not the correct explanation of A.
(C) A is true, but R is false.
(D) A is false, but R is true.
Answer: (A)
