Science MCQ Class 9, Chapter-2, Is Matter Around Us Pure

This article covers NCERT based MCQ of Class 9th, Chapter-2, Is Matter Around Us Pure with brief explanation for competitive exams like HTET, SSC and all other state competition exams. 

Along with MCQ, Chapter Key-Points for quick learning NCERT related facts are also discussed below. 

Right Answer for MCQ will be highlighted on Hover / Click on the option.

Download PDF, 100+ MCQ, Free !

Summary of the Chapter-2-Is Matter Around Us Pure with Key-Points:

• A mixture is made up of two or more substances (elements or compounds) combined in any ratio. These substances can be separated using suitable methods.
• A solution is a uniform mixture of two or more substances. The primary component is the solvent, while the substance present in a smaller amount is the solute.
• The concentration of a solution refers to the quantity of solute per unit volume or mass of the solution.
• Substances that do not dissolve in a solvent and have particles visible to the naked eye form a suspension, which is a non-uniform (heterogeneous) mixture.
• Colloids are heterogeneous mixtures with particles too small to see but large enough to scatter light. They have practical uses in industries and daily life. The dispersed particles are known as the dispersed phase, while the surrounding substance is the dispersion medium.
• Pure substances are either elements or compounds. An element is a basic form of matter that cannot be broken down into simpler substances by chemical means. A compound consists of two or more different elements chemically bonded in a fixed ratio.
• The properties of a compound differ from those of its individual elements, whereas mixtures retain the characteristics of their components.

NCERT Based MCQ with Explanation:

1. What is the physical nature of matter according to ancient Indian philosophy?

A) Matter is continuous

B) Matter is made of particles

C) Matter is made of five basic elements

D) Matter has no specific form

Explanation: Ancient Indian philosophers believed that everything, living or non-living, is made up of five basic elements: air, earth, fire, sky, and water, known as the "Panch Tatva."

2. Which of the following statements best explains why matter is classified based on its physical properties?

A) To understand the chemical composition

B) To identify how substances interact with each other

C) To distinguish the shape and size of particles

D) To differentiate states of matter such as solid, liquid, and gas

Explanation: Matter is classified based on physical properties like shape, volume, and compressibility to distinguish between solids, liquids, and gases.

3. What happens to the particles of potassium permanganate when it is dissolved in water?

A) They react chemically with water.

B) They disappear.

C) They spread throughout the water.

D) They settle at the bottom.

Explanation: When potassium permanganate is dissolved in water, its particles distribute evenly throughout the solution, illustrating that matter is made up of particles.

4. What property of matter is demonstrated when the smell of perfume spreads in a room?

A) Matter is made up of particles.

B) Particles of matter are continuously moving.

C) Particles of matter have spaces between them.

D) Particles of matter attract each other.

Explanation: The spreading of perfume illustrates the continuous motion of particles, which allows them to diffuse through the air.

5. Which observation supports the idea that particles of matter are very small?

A) They are visible to the naked eye.

B) They cannot be seen even with a microscope.

C) A small amount of potassium permanganate colors a large volume of water.

D) They are stationary in liquids.

Explanation: This observation shows that there must be millions of tiny particles in just a few crystals, highlighting the small size of particles.

6. Which of the following is NOT a characteristic of the particles of matter?

A) They have spaces between them.

B) They are in constant motion.

C) They can move in any direction.

D) They repel each other strongly.

Explanation: Particles of matter attract each other to varying degrees, depending on the state of matter (solid, liquid, gas), rather than repelling each other.

7. What does the Tyndall effect demonstrate?

A) Particles of matter attract each other.

B) Light is scattered by particles in a colloid.

C) Particles of a solution are invisible.

D) Liquids have a definite shape.

Explanation: The Tyndall effect occurs when light is scattered by colloidal particles, making the path of the light visible.

8. Which of the following is an example of a homogeneous mixture?

A) Oil and water

B) Sand and salt

C) Sugar dissolved in water

D) Iron filings and sulphur powder

Explanation: A homogeneous mixture has a uniform composition throughout, such as sugar dissolved in water, where the sugar particles are evenly distributed.

9. Why is air considered a mixture rather than a pure substance?

A) It consists of only one type of gas.

B) It is a compound of nitrogen and oxygen.

C) It contains multiple gases that retain their properties.

D) It can be separated by chemical methods.

Explanation: Air is a mixture of gases (like nitrogen, oxygen, and carbon dioxide) that do not chemically combine and can be separated by physical means.

10. What is the main difference between a compound and a mixture?

A) Compounds can be separated easily; mixtures cannot.

B) Compounds have fixed proportions; mixtures have variable proportions.

C) Mixtures are always homogeneous; compounds are always heterogeneous.

D) Mixtures consist of elements only; compounds consist of molecules only.

Explanation: In compounds, elements combine in fixed ratios to form a new substance, whereas mixtures can vary in composition and still retain individual properties.

11. Which separation technique is suitable for separating a mixture of salt and water?

A) Filtration

B) Evaporation

C) Distillation

D) Decantation

Explanation: Evaporation removes water by heating the mixture until the water evaporates, leaving the salt behind.

12. What type of mixture is milk classified as?

A) Solution

B) Suspension

C) Colloid

D) Pure substance

Explanation: Milk is a colloid because it consists of tiny particles dispersed in a liquid medium that do not settle out easily and can scatter light.

13. Which property of a solution makes it stable?

A) The solute particles settle down over time.

B) Solute particles can be filtered easily.

C) The solute particles do not scatter light.

D) The solute particles can be seen by the naked eye.

Explanation: In a solution, the solute particles are very small and do not scatter light, making the mixture stable and homogeneous.

14. What is the dispersed phase in a colloid?

A) The medium in which particles are suspended

B) The particles that are suspended

C) The dissolved ions

D) The visible light

Explanation: The dispersed phase in a colloid refers to the particles that are distributed throughout the dispersion medium.

15. Which of the following is NOT a property of suspensions?

A) They are heterogeneous mixtures.

B) Their particles settle when left undisturbed.

C) Their particles are visible to the naked eye.

D) Their particles cannot be separated by filtration.

Explanation: Particles in a suspension are large enough to be seen and can be separated from the mixture using filtration, unlike solutions.

16. Which method is used to separate components in a colloid?

A) Distillation

B) Filtration

C) Centrifugation

D) Evaporation

Explanation: Centrifugation is used to separate colloidal particles by spinning the mixture rapidly, causing denser particles to move outward.

17. Which of the following best describes a saturated solution?

A) It can dissolve more solute at a given temperature.

B) It contains as much solute as can dissolve at that temperature.

C) It is an unstable mixture.

D) It only contains one type of substance.

Explanation: A saturated solution holds the maximum amount of solute that can be dissolved at a particular temperature, making it unable to dissolve more.

18. Which of the following describes a physical change?

A) Burning of wood

B) Rusting of iron

C) Melting of ice

D) Digestion of food

Explanation: Melting of ice is a physical change because it involves a change in state (solid to liquid) without altering the chemical composition of water.

19. Which element is liquid at room temperature?

A) Sodium

B) Mercury

C) Iron

D) Calcium

Explanation: Mercury is the only metal that is liquid at room temperature due to its low melting point compared to other metals.

20. What type of change occurs when a compound is formed?

A) Physical change

B) Chemical change

C) Biological change

D) No change

Explanation: A compound is formed through a chemical change where elements react and bond in fixed proportions, resulting in new substances with different properties.