NCERT Solutions Class 10 Science Chapter 2 Is Matter Around us Pure

NCERT Solutions Class 10 Science Chapter 2 Is Matter Around us Pure

NCERT Solutions Class 10 Science Chapter 2 Is Matter Around us Pure: National Council of Educational Research and Training Class 10 Science Chapter 2 Solutions – Is Matter Around us Pure. NCERT Solutions Class 10 Science Chapter 2 PDF Download.

NCERT Solutions Class 10 Science Chapter 2: Overview







Chapter Name

Is Matter Around us Pure

Exercise Solutions

NCERT Solutions Class 10 Science Chapter 2 – Is Matter Around us Pure

1) What is meant by a substance?

Ans-Substance is defined as anything which consists of one or more type of particles which forms matter.

2) List the points of difference between homogeneous and heterogeneous mixtures.


Homogeneous Mixture-

  1. Homogeneous mixture is pure.
  2. It consists of only one type of particle.
  3. Homogeneous mixture is uniform.
  4. Homogenous mixture is mainly inseparable.
  5. Examples-Water, air ,steel etc.

Heterogeneous Mixture-

  1. Heterogeneous mixture is impure.
  2. It consists of two or more types of particles.
  3. Heterogeneous mixtures can be separated.
  4. Examples- sand and water, oil and water etc.

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2) How are SOL ,solution and suspension different from each other?


Sol-Sol is a colloidal liquids solution in which particles are spread uniformly.Sol is in liquid or gaseous state.

Solution-Solution is a homogeneous mixture of two or more substances.Solute particles are inseparable from solvent in a solution.

Suspension-It is a system in which particles are suspended in liquid and does not dissolve, they can be separated easily. Particles are visible to eyes which are suspended in liquid.

3)To make a saturated solution 36 gram of sodium chloride is dissolved in hundred gram of water at 293 k. Find the concentration of this temperature.

Ans- To find concentration of solution,

Mass of solute- 36g

Mass of solvent- 100g

Mass of solution- 100+36


Concentration -mass of solute/solution× 100



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1) How will you separate a mixture containing kerosene and petrol (difference in their boiling point is more than 25 degree Celsius) which are miscible with each other.

Ans-By the process of distillation we can separate kerosene and petrol which are miscible with each other. Distillation is a method of separation of two liquids which are miscible with each other.

2)Name the technique to separate,

 1)Butter from curd 2) Salt from seawater3) Camphor from salt.


1) Butter is separated from curd by the process of centrifugation where curd is churned well to obtain butter which is an instrument called churner.

2)Evaporation method is used to separate salt from seawater water gets evaporated leaving behind salt.

3) Camphor is separated from salt by the process of sublimation. camphor burns into vapour leaving salt behind.

3) What type of mixture are separated by the technique of crystallization?

Ans-Solid liquid mixtures are separated to obtain pure solid by the technique of crystallization.

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1)Classify the following as chemical or physical changes.

1) Cutting of trees

2)Melting of butter in pan

3)Rusting of Almirah

4)Boiling of water to form stem

5) Passing of electric current through water and water breaking down to hydrogen and oxygen

6)Dissolving of common salt in water.


1 Cutting of trees- Physical change. No change in composition.

2 Melting of butter in pan- Physical change- No change in composition

3 Rusting of Almirah- Chemical change – Change in composition of Almirah through rusting.

4)Boiling of water to form stem- Physical change

5)Passing of electric current through water and water breaking down to hydrogen and oxygen- Chemical change.

6) Dissolving common salt in water- physical change.

2) Try separating the things around you as  pure substances and mixtures.

Ans- Sugar ,salt ,copper plate etc. are pure  substances and milk ,salt and water,air, water and soil are mixtures.

Exercise Question Solution:

1)Which separation techniques will you apply for the separation of the following

  • Sodium chloride from its solution in water
  • Ammonium chloride from a mixture containing sodium chloride and ammonium chloride.
  • Small pieces of metal in engine oil of car
  • Different pigments from an extract of flower petals.
  • Butter from curd
  • Oil from water
  • Tea leaves from tea
  • Iron pins from sand.
  • Wheat grains from husk

10)Fine mud particles suspended.


1) Evaporation water gets evaporated and sodium chloride is left behind.

2) Sublimation ammonium chloride get evaporated and sodium chloride is left.

3)Filtration method by filtration the small pieces of metal are separated from engine oil.



6) Separated with the help of separation funnel.

7) Filtration method

8) Magnetic separation

9) Winnowing wheat is separated from husk by throwing it in the air as husk is lighter than wheat and it is blown in air


2) Write the steps you would use for making tea. Use the words solutions solvent solute soluble insoluble filtrate and residue.

Ans-Take a vessel and a cup of milk half cup of water and sugar. Allow it to heat. Add tea leaves to it. Your water is solvent milk is solvent still leaves and sugar are solute. After given appropriate heat sugar dissolves in water and milk forming uniform solution. Tea leaves are in soluble in the solution of milk and water but gives colour and taste to the solution. After boiling filter the solution in a cup residue left is tea leaves which were in soluble and your tea is ready.


Pragya tested the solubility of three different substances at different temperature and collected the data as given below ( results are given in the following table as g of substances dissolve 100 grams of water to form saturated solution)

a) What mass of potassium nitrate would be needed to produce a saturated solution of potassium nitrate in 50 grams of water at 313 k?

b) Pragya make a saturated solution of potassium chloride in water at 353 K and leaves the solution to cool at room temperature what would she observed as the solution will cool? Explain

c) Find the solubility of salt solution at 293 K .which salt solution has the highest solubility at this temperature.

d) What is the effect of change of temperature on solubility of salt.


a) 313 k g of potassium nitrate dissolved are 62 grams.

To produce saturated solution of 50 grams,




b) As the solution cool, some crystals of potassium nitrate will be formed ,at room temperature solubility decreases.


c) To find the celebrity of each salt at 293 k

Solubility of potassium nitrate is 32 g

Solubility of sodium chloride is 36 g

Solubility of potassium chloride is 35g

Solubility of ammonium chloride is 37 g

Highest of all solubility is of ammonium chloride which is 37 g.


d) As temperature increases solubility increases.

4) Explain the following giving example.

Saturated solution, pure substance, colloid, suspension.


Saturated solution- Solutions which has a large amount of solute in them that further addition of solute would not dissolve it in a solution are called saturated solutions. For example soda water, juice powders, too much of sugar in water etc.

Pure substances-substances made up of only one type of particles or only one kind of elements are called pure substances.

Colloid- a substance made of solve it in which smaller particles are suspended is called colloid. For example mod and water mist etc

Suspension-heterogeneous mixture in which particles can be seen suspended inside the solvent is called suspension.

For example sand particles in water, copper feelings in water etc.

5)Classify each of the following is homogeneous and heterogeneous mixture.

Soda water, wood,air ,soil vinegar, filter tea.

Ans-Homogeneous mixture- soda water air vinegar filter tea.

These mixtures are uniform and cannot be separated. They are in one phase that particles are not visible.

Heterogeneous mixture-wood ,soil

These mixtures are not uniform they have two or more substances present in them and can be separated.

6) How would you confirm that a colourless liquid given to you is pure water?

Ans-By checking its boiling point we can confirm that given liquid is pure water. The boiling point of pure water is 100°C pure water boils perfectly at 100°C.

7) which of the following materials pores in the category of pure?

Ice ,milk ,iron ,hydrochloric acid calcium oxide, mercury, brick,wood, air.

Ans-Ice, iron ,hydrochloric acid, calcium oxide, mercury, are substances because they contains 1 phase and uniform composition.

8)Identify the solution among the following mixtures. Soil sea water air coal soda water.

Ans-Sea water soda water and air are solutions which has two or more substances present in them.

9) Which of the following will show tyndall effect?

Salt solution, milk, copper sulphate solution,tin, silicon.

Ans- Among the following on the milk shows  tyndall effect as it is a colloidal mixture.

10) Classify the following into elements compounds and mixtures.

Sodium ,soil ,sugar solution, silver, calcium carbonate,tin, silicon, coal, air, soap methane ,carbon dioxide blood.

Ans-Elements– Sodium, silver, tin, silicon

Elements- An element is a substance that is made of only one type of particles which cannot be broken further.

Compounds– Calcium carbonate, carbon dioxide, methane.

A substance made of two or more elements which are chemically bonded are called compounds.

Mixtures– Soil sugar ,solution air, blood coal

Mixture is defined a substance made by mixing two or more substances.

11) Which of the following are chemical changes?

Growth of plants ,rusting of iron,mixing of iron filings and sand, cooking of food, digestion of food, freezing of water ,burning of a candle.

Ans-Chemical changes are growth of plants ,rusting of iron cooking of food, digestion of food, burning of candles.

Change in chemical composition of substance is considered as chemical change in a substance.

Updated: December 8, 2021 — 11:37 pm

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