Class 9 Science Exploration Chapter 5 MCQs – Exploring Mixtures and their Separation – practice helps students understand about Mixtures and their Separation clearly and quickly. This chapter explains homogeneous and heterogeneous mixtures, concentration of solutions, solubility and solubility curves. It also covers separation methods such as crystallization, distillation, paper chromatography, sublimation, centrifugation and coagulation, along with suspensions, colloids and the Tyndall effect. These multiple choice questions with answers follow the latest NCERT Exploration textbook and test both concepts and numerical problems on percentage concentration. Practising them regularly improves accuracy and confidence for class tests, periodic assessments and annual exams.
Class 9 Science Exploration Chapter 5 MCQs with Answer
Class 9 Science Chapter 5 MCQs Set 1
Q1. Which mixture has a uniform composition throughout?
[A]. Oil and water
[B]. Sand and water
[C]. Sugar dissolved completely in water
[D]. Chalk powder and water
Q2. In a solution of sugar and water, which substance is the solvent?
[A]. Neither substance
[B]. Both are solutes
[C]. Sugar
[D]. Water
Q3. What does the concentration of a solution describe?
[A]. Only the colour of the solute
[B]. The amount of solute in a given amount of solvent or solution
[C]. Only the temperature of the solvent
[D]. The shape of the container
Q4. Ten grams of salt is dissolved in 90 g of water. What is the mass by mass percentage?
[A]. 10%
[B]. 11.1%
[C]. 9%
[D]. 90%
Q5. A solution contains 5 g of glucose in a final volume of 100 mL. What is its concentration?
[A]. 95% m/v
[B]. 50% m/v
[C]. 5% v/v
[D]. 5% m/v
Class 9 Science Chapter 5 MCQs Set 2
Q6. Thirty millilitres of juice concentrate is diluted to a final solution volume of 150 mL. What is its volume percentage?
[A]. 50%
[B]. 20%
[C]. 30%
[D]. 5%
Q7. A powder contains 4% zinc oxide by mass. How much zinc oxide is present in 300 g of powder?
[A]. 4 g
[B]. 8 g
[C]. 75 g
[D]. 12 g
Q8. What is a saturated solution at a given temperature?
[A]. A solution with no solute
[B]. A solution that cannot dissolve more of that solute
[C]. A mixture with two liquid layers
[D]. A solution containing only gases
Q9. How does the solubility of most solid solutes in water change when temperature rises?
[A]. It generally increases
[B]. It is always unchanged
[C]. It always becomes zero
[D]. It generally decreases to zero
Q10. What generally happens to the solubility of a gas in a liquid when temperature rises?
[A]. It becomes unlimited
[B]. It doubles in every case
[C]. It always remains unchanged
[D]. It decreases
Class 9 Science Chapter 5 MCQs Set 3
Q11. A solution contains 287 g of a solute in 100 g water at 60 °C. Only 241 g can remain dissolved at 40 °C. How much solid separates on cooling, with no water lost?
[A]. 46 g
[B]. 287 g
[C]. 241 g
[D]. 528 g
Q12. What is the main purpose of crystallization when purifying a solid?
[A]. To mix it with insoluble sand
[B]. To convert it permanently into a gas
[C]. To make two liquids immiscible
[D]. To obtain pure crystals from its solution
Q13. Why is a hot saturated solution usually cooled slowly during crystal preparation?
[A]. To turn the solute into an alloy
[B]. To give particles time to form larger, well-shaped crystals
[C]. To increase the amount of solvent continuously
[D]. To prevent all solid formation
Q14. Which method allows water to be recovered from a salt solution?
[A]. Distillation
[B]. Filtration alone
[C]. A separating funnel
[D]. Magnetic separation
Q15. Why can acetone and water be separated by simple distillation?
[A]. Acetone is an insoluble solid
[B]. They have the same boiling point
[C]. Their boiling points differ sufficiently
[D]. They are immiscible
Class 9 Science Chapter 5 MCQs Set 4
Q16. What is the function of a condenser in distillation?
[A]. To increase the solute’s mass
[B]. To filter insoluble sand
[C]. To cool vapour and turn it into liquid
[D]. To stir the original mixture
Q17. Which method is used to separate miscible liquid components with relatively close boiling points?
[A]. Fractional distillation
[B]. Handpicking
[C]. Magnetic separation
[D]. Sedimentation
Q18. Why do different dyes separate during paper chromatography?
[A]. The paper melts into the solvent
[B]. They all become insoluble solids immediately
[C]. They all move at exactly the same rate
[D]. They interact differently with the paper and solvent
Q19. Where should the initial ink spot be placed relative to the solvent level in paper chromatography?
[A]. Completely submerged
[B]. At the bottom of the container
[C]. Below the solvent surface
[D]. Above the solvent level
Q20. Which apparatus is suitable for separating mustard oil and water?
[A]. A sieve
[B]. A thermometer
[C]. A separating funnel
[D]. A magnet
Class 9 Science Chapter 5 MCQs Set 5
Q21. Why does mustard oil form the upper layer when mixed with water?
[A]. It is less dense than water and does not mix with it
[B]. It dissolves completely in water
[C]. It is denser than water
[D]. It changes into water
Q22. Which change is called sublimation?
[A]. Liquid to vapour only
[B]. Solid directly to vapour
[C]. Liquid directly to solid
[D]. Gas directly to liquid
Q23. Camphor vapour forms solid camphor on a cool surface without becoming liquid. What is this change?
[A]. Boiling
[B]. Deposition
[C]. Evaporation
[D]. Melting
Q24. Which pair of metals makes brass?
[A]. Zinc and aluminium
[B]. Copper and zinc
[C]. Copper and tin
[D]. Iron and tin
Q25. Which observation is characteristic of a suspension?
[A]. Complete dissolution of every particle
[B]. Permanent uniformity at particle level
[C]. Visible particles that can settle on standing
[D]. No particles larger than 1 nm
Class 9 Science Chapter 5 MCQs Set 6
Q26. Why is alum added to muddy water during coagulation?
[A]. To dissolve all the mud
[B]. To make particles smaller
[C]. To make fine particles form larger clumps
[D]. To convert water into gas
Q27. Which statement correctly describes colloidal particles?
[A]. They remain dispersed and scatter light
[B]. They always settle rapidly
[C]. They form a completely separate bottom layer immediately
[D]. They are smaller than all solution particles
Q28. Why is a beam of light visible in diluted milk but not in a clear salt solution?
[A]. Salt solution has no particles at all
[B]. Salt particles are larger than milk particles
[C]. Milk’s colloidal particles scatter light
[D]. Milk converts light into salt
Q29. In a colloid, what is the dispersion medium?
[A]. The substance in which the dispersed particles are distributed
[B]. The light passing through the mixture
[C]. Only the solid particles
[D]. The separated sediment
Q30. Which method separates components by rapidly spinning a mixture?
[A]. Chromatography
[B]. Centrifugation
[C]. Sublimation
[D]. Crystallization
Class 9 Science Exploration Chapter 5 MCQ with Answer
Important Concepts to Remember from Class 9 Science Chapter 5 Exploring Mixtures and their Separation
- A homogeneous mixture (solution) has uniform composition throughout, while a heterogeneous mixture does not.
- Concentration is the amount of solute in a given amount of solvent or solution. It can be expressed as % m/m, % m/v or % v/v.
- Solubility is the maximum amount of solute that dissolves in 100 g of solvent at a given temperature. Solubility of solids generally increases with temperature, while that of gases decreases.
- Crystallization separates a pure solid from its saturated solution and works on differences in solubility at different temperatures.
- Distillation separates miscible liquids whose boiling points differ by about 25 °C or more. Fractional distillation is used when the difference is smaller.
- Paper chromatography separates components based on their different rates of movement on the paper with the solvent.
- A separating funnel separates immiscible liquids based on their different densities; the denser liquid forms the lower layer.
- Sublimation is the direct change of a solid into vapour, and deposition is the reverse. Camphor, naphthalene and dry ice sublime.
- Centrifugation uses rapid spinning to separate heavier particles, and coagulation uses a coagulant like alum to clump fine particles together.
- Solution particles are less than 1 nm, colloid particles are 1–1000 nm and suspension particles are more than 1000 nm. Colloids and suspensions show the Tyndall effect, but solutions do not.
Tips to Score Better in Chapter 5 Mixtures MCQs
- Remember that the mass of solution = mass of solute + mass of solvent when solving % m/m questions.
- Learn one everyday example for each separation method, such as alum for coagulation or camphor for sublimation.
- Compare solutions, suspensions and colloids on particle size, settling, filtration and Tyndall effect.
- Read solubility curves carefully to see which substance changes more with temperature.
- Note that alloys like brass and bronze are homogeneous and cannot be separated by physical methods.
Regular practice of these Class 9 Science Exploration Chapter 5 MCQs builds a strong understanding of mixtures and separation techniques. The questions cover definitions, concentration numericals, solubility graphs and real-life applications like ORS preparation, blood separation, water purification and petroleum refining. This makes the chapter practical and easy to relate to. After each attempt, review the questions you got wrong and revisit the related textbook section to strengthen your concepts for exams.
Chapter 5 MCQs and NCERT Solutions
Once you are confident with these multiple choice questions, move on to the detailed exercise answers to complete your preparation. Our NCERT Solutions for Class 9 Science Exploration Chapter 5 provide step-by-step explanations for all textbook questions, including concentration problems, solubility table questions and separation method diagrams. Practising MCQs alongside solutions helps you master every part of “Exploring Mixtures and their Separation” and prepares you well for school tests and annual examinations.
