Why is crystallisation often preferred over evaporation to purify a solid?

some solids decompose on strong heating, which crystallisation avoids

Why must a mixture of salt and water NOT be separated by filtration?

the salt is dissolved and passes through the filter paper

Which separation relies on a difference in particle SIZE (insoluble solids vs liquid)?

filtration. The core fact here is - An ion forms when an atom gains or loses electrons; charge = (protons) - (electrons), so the sign and magnitude follow directly => substituting the given counts gives the stated species; therefore the answer = filtration. That fits the listed correct option directly - Correct. As for the rest: option B) 'distillation' is incorrect: Distillation relies on boiling-point differences, not particle size; option C) 'chromatography' misses the point - Chromatography relies on differing movement rates, not simple size sieving. Hence the answer is A) filtration.

Class 9 · Science · Chemistry

Is Matter Around Us Pure MCQs

Take an interactive Is Matter Around Us Pure quiz for Class 9 Science - tap an answer for instant feedback and a step-by-step solution. These are a few sample questions; practice the full Is Matter Around Us Pure set free on the RankByte app.

Topics covered

Mixtures vs Pure SubstancesSolutions, Suspensions and ColloidsSeparation of Mixtures (Distillation, Chromatography, etc.)Physical and Chemical ChangesElements and CompoundsTypes of MixturesSolutions and ConcentrationMethods of SeparationColloids, Suspensions and Tyndall EffectMixtures, solutions, suspensions, colloids, separation

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Focused MCQ quizzes for each topic.

Colloids, Suspensions and Tyndall Effect Elements and Compounds Methods of Separation Mixtures vs Pure Substances Mixtures, solutions, suspensions, colloids, separation Physical and Chemical Changes Separation of Mixtures (Distillation, Chromatography, etc.)Solutions and Concentration Solutions, Suspensions and Colloids Types of Mixtures

Is Matter Around Us PureQuiz - Solve & Score

A few sample questions with instant answers and solutions - the full set is in the app.

Q1. Why is crystallisation often preferred over evaporation to purify a solid?
- A.some solids decompose on strong heating, which crystallisation avoids
- B.evaporation is impossible for solids
- C.crystallisation needs no solvent
- D.evaporation always adds impurities
Answer: A. some solids decompose on strong heating, which crystallisation avoids
Q2. Why must a mixture of salt and water NOT be separated by filtration?
- A.the salt is dissolved and passes through the filter paper
- B.salt is magnetic and sticks to the funnel
- C.water cannot pass through filter paper
- D.the salt reacts with the paper
Answer: A. the salt is dissolved and passes through the filter paper
Q3. Which separation relies on a difference in particle SIZE (insoluble solids vs liquid)?
- A.filtration
- B.distillation
- C.chromatography
- D.a separating funnel
Answer: A. filtration
The core fact here is - An ion forms when an atom gains or loses electrons; charge = (protons) - (electrons), so the sign and magnitude follow directly => substituting the given counts gives the stated species; therefore the answer = filtration. That fits the listed correct option directly - Correct. As for the rest: option B) 'distillation' is incorrect: Distillation relies on boiling-point differences, not particle size; option C) 'chromatography' misses the point - Chromatography relies on differing movement rates, not simple size sieving. Hence the answer is A) filtration.