Methods of Separation in Everyday Life – MCQs with Answers and Explanations
Class 6
Science
Chapter 9
Methods of Separation in Everyday Life — 40 Topic-wise MCQs
CBSE Board Examinations
Answer each MCQ and click "Show Answer & Explanation" to reveal the correct option and reasoning.
Exam Guidance
- MCQs test quick recall and conceptual understanding. Read each option carefully and eliminate wrong choices.
- Explanations reinforce why an option is correct and clarify related concepts from the chapter.
- Use these MCQs for timed practice or as warm-up exercises before tests.
Basics of Separation
1Which of the following is a heterogeneous mixture?
Correct: C. Sand and iron filings mixed.
Explanation: A heterogeneous mixture has components that are not uniformly distributed and can be seen separately. Sand and iron filings form a mixture with visible different parts. Sugar/salt dissolved in water and air are homogeneous (uniform) at observable scale.2Which physical property is most useful to separate iron filings from sand?
Correct: C. Magnetic property.
Explanation: Iron is magnetic and can be attracted by a magnet; sand is not magnetic. This difference allows magnetic separation. Particle size or solubility are not reliable here and boiling point is irrelevant for solids in this context.3Which method would you use to separate a soluble solid from a liquid when you want the solid back?
Correct: B. Evaporation.
Explanation: Evaporation removes the solvent (liquid) leaving the dissolved solid behind. Filtration cannot separate dissolved solids; magnetic separation and sieving are for different properties.4Which of the following is NOT a physical method of separation?
Correct: C. Chemical reaction to form a precipitate.
Explanation: A chemical reaction changes substances chemically and is not a physical separation. Filtration, distillation and sieving separate components using physical properties without changing chemical identities.Handpicking and Winnowing
5If grains are mixed with stones, which method is best to separate them?
Correct: B. Handpicking.
Explanation: Handpicking is suitable when components are large and visible (stones and grains). Winnowing separates lighter husk from grain, filtration is for solids in liquids, and evaporation is for removing a solvent.6Winnowing separates materials based on which property?
Correct: C. Density/weight.
Explanation: Winnowing uses wind to blow away lighter, less dense particles (like chaff), while heavier grains fall back due to greater weight.7Which is an advantage of handpicking?
Correct: C. Simple and cost-free.
Explanation: Handpicking needs no equipment and is easy for visible components. It cannot remove microscopic impurities or dissolved substances and does not need complex tools.8Winnowing would not be useful for separating which of the following?
Correct: B. Sand from sugar.
Explanation: Winnowing separates by weight using air; sand and sugar have similar densities and won't separate easily by wind. Other options involve lighter and heavier components where winnowing works.Sieving
9Sieving separates particles based on:
Correct: B. Particle size.
Explanation: Sieving uses a mesh; smaller particles pass through, larger ones are retained. It is used for flour, aggregates and grain cleaning where size difference exists.10Which kitchen tool is commonly used for sieving?
Correct: B. Sieve/strainer.
Explanation: A sieve or strainer separates lumps or larger particles from flour or liquids. Other tools serve different purposes like grinding or separating immiscible liquids.11Sieving cannot be used to separate:
Correct: C. Salt dissolved in water.
Explanation: Sieving separates only undissolved particles by size. Dissolved solids pass through any mesh. The other options involve undissolved particles with size differences.12Industrial sieves differ from hand sieves because they:
Correct: B. Have adjustable mesh sizes and are mechanised.
Explanation: Industrial sieves are designed for speed and volume with adjustable meshes and mechanical motion to improve efficiency; they don't involve chemical changes or evaporation.Sedimentation & Decantation
13What principle causes sedimentation?
Correct: B. Gravitational settling of heavier particles.
Explanation: Sedimentation relies on gravity to pull heavier suspended particles down to the bottom over time.14After sedimentation, the clear liquid is removed by:
Correct: A. Decantation.
Explanation: Decantation involves gently pouring out the clear liquid after sedimentation, leaving sediment behind. Filtration can be used later to remove remaining fine particles.15Which factor will NOT increase the rate of sedimentation?
Correct: C. Increased stirring.
Explanation: Stirring keeps particles suspended and slows sedimentation. Larger size, higher density and lower viscosity help particles settle faster.16If muddy water is left standing undisturbed, which process cleans it partly?
Correct: B. Sedimentation.
Explanation: Standing lets heavier particles settle by gravity, which is sedimentation. Filtration can follow to remove remaining small particles.Filtration
17In filtration, the solid left on the filter is called:
Correct: B. Residue.
Explanation: Residue is the solid retained on the filter. The liquid that passes through is the filtrate.18Which of these is an example of filtration at home?
Correct: B. Using a coffee filter.
Explanation: Coffee filters separate coffee grounds (insoluble solids) from brewed coffee (liquid). Boiling is heating, evaporation removes solvent, and magnets separate magnetic solids.19Filtration cannot remove:
Correct: C. Dissolved salt from water.
Explanation: Dissolved ions are at molecular level and pass through filter pores with liquid. Filtration removes insoluble particles only.20Which filter material is commonly used in laboratory filtration?
Correct: A. Filter paper.
Explanation: Filter paper is a standard porous material used in labs to separate fine insoluble solids from liquids. Muslin cloth is used at home; sand is part of a sand filter, and magnet is unrelated.Evaporation & Crystallisation
21How is salt obtained from seawater on a large scale?
Correct: B. Evaporation and crystallisation.
Explanation: Large shallow pans in salt pans allow water to evaporate in sun, leaving salt crystals behind. Distillation is not economical for large-scale salt production.22Which statement is true about evaporation?
Correct: B. It converts liquid to vapour without collecting vapour.
Explanation: Evaporation removes solvent as vapour which disperses; vapour is not usually collected (unlike distillation where vapour is condensed and collected).23Crystallisation is used when we want:
Correct: B. To obtain the solute in crystalline form.
Explanation: Crystallisation gives the solute as solid crystals which can be collected; it's used for sugar, salt and other substances where crystalline form is desired.24Which factor speeds up evaporation of water from wet clothes?
Correct: B. Strong sunlight and wind.
Explanation: Sunlight provides energy for evaporation and wind removes vapour, increasing evaporation rate. Humidity and cold still air slow it down.Distillation
25Distillation separates substances mainly using differences in:
Correct: B. Boiling points.
Explanation: Distillation is based on selective boiling and condensation; liquids with different boiling points vaporise at different temperatures and can be separated.26Which method would you use to get pure water from seawater if you want the water back?
Correct: C. Distillation.
Explanation: Distillation condenses water vapour to collect pure water; evaporation would remove water as vapour but does not collect it for reuse.27Simple distillation is most suitable for separating:
Correct: C. Two miscible liquids with very different boiling points.
Explanation: Simple distillation separates liquids based on boiling point differences; it is not for solids or magnetic separation.28Which is a necessary part of a distillation setup?
Correct: A. Condenser to cool vapour.
Explanation: A condenser cools hot vapour, turning it back to liquid so it can be collected. Magnets, sieves and filter paper are not part of distillation's core apparatus.Magnetic Separation
29Magnetic separation is most suitable to separate:
Correct: B. Iron filings from sand.
Explanation: Magnetic separation exploits magnetic attraction; iron is magnetic and can be removed using a magnet. The other mixtures involve solubility or immiscible liquids.30Which waste management task commonly uses magnetic separation?
Correct: B. Separating ferrous metals for recycling.
Explanation: Magnetic separators in recycling plants remove iron and steel from mixed waste, aiding recycling and protecting equipment.31Why can't magnetic separation be used to separate aluminium from sand?
Correct: B. Aluminium is non-magnetic.
Explanation: Magnetic separation only works for magnetic (ferrous) materials; aluminium is not attracted to magnets so it cannot be separated this way.32Magnetic separation is environmentally useful because it:
Correct: B. Separates ferrous metals for recycling.
Explanation: Collecting ferrous metals for recycling reduces landfill and conserves resources; magnetic separation is efficient and widely used in recycling plants.Chromatography & Separating Immiscible Liquids
33Paper chromatography separates mixtures based on differences in:
Correct: B. Solubility and affinity for paper.
Explanation: Different components dissolve differently in the solvent and interact with the paper, so they travel at different rates and separate.34An apparatus used to separate two immiscible liquids in the lab is called:
Correct: B. Separating funnel.
Explanation: A separating funnel allows immiscible liquids to form layers which can be drained separately from the bottom tap.35Which pair are immiscible?
Correct: B. Oil and water.
Explanation: Oil and water do not mix and form separate layers — they are immiscible. Salt/sugar dissolve in water and alcohol mixes with water (miscible).36In paper chromatography, if a spot moves very little with the solvent, it means:
Correct: B. It has strong affinity for the paper.
Explanation: If a component sticks to the paper more than it dissolves in the solvent, it travels less distance with the solvent front.Combined Methods & Application
37To separate a mixture of sand, salt and iron filings completely, the correct order of methods is:
Correct: B. Magnetic separation → Add water and filtration → Evaporation.
Explanation: First remove iron by magnet, dissolve salt in water and filter to remove sand, then evaporate filtrate to obtain salt crystals. This sequence uses magnetic property, solubility and evaporation respectively.38Which method sequence best purifies muddy water for safe household use (basic level)?
Correct: B. Sedimentation → Filtration → Boiling.
Explanation: Let solids settle (sedimentation), filter remaining particles, then boil water to kill microbes. Evaporation alone won't collect water; distillation is optional but more complex.39Why is combining methods often necessary to fully separate complex mixtures?
Correct: A. Because one method may not address all differing properties.
Explanation: Complex mixtures contain components with different physical properties; using a sequence exploits each property (magnetism, solubility, size) to separate all parts effectively.40Which of the following is a correct safety precaution while performing separation experiments?
Correct: B. Wear safety goggles and follow teacher's instructions.
Explanation: Safety includes protective gear, adult supervision and careful handling of equipment and heat sources. The other options are dangerous practices.