# NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations - Students appearing in the board exams must go through the Class 10 Science Chapter 1 NCERT solutions. Chemical Reactions and Equation is one of the most important chapters in the NCERT books for Class 10 Science. This NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations will help you in board exam as well as in competitive exam preparation. All the questions with detailed explanation are provided in the NCERT Solutions for Class 10 Science Chapter 1. You can also refer to the NCERT solutions for Class 10 for other subjects here.

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• Chemical Reactions and Equations Class 10 NCERT Exemplar Solutions
• Chemical Reactions and Equation Class 10 NCERT Chapter Notes

## Chemical Reactions and Equations -Topics

• Chemical reactions and equations

• Chemical equations

• Types of chemical equations

• Effects of oxidation reactions in everyday life?

## Topic 1.1 Chemical equations:

Q 1 . Why should a magnesium ribbon be cleaned before burning in air?

Magnesium is a very reactive metal so it reacts with oxygen to form a layer of magnesium oxide on its surface.

This layer is stable oxide so prevent further reaction of magnesium with oxygen. To remove this layer a magnesium ribbon is cleaned using sandpaper before burning in air.

Q 2. (i) Write the balanced equation for the following chemical reactions.

Hydrogen + Chlorine → Hydrogen chloride

The balanced equation for the following chemical reactions is given as :

Q 2. (ii) Write the balanced equation for the following chemical reactions.

Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride

The balanced equation for the following chemical reactions is given as :

Q2. (iii) Write the balanced equation for the following chemical reactions.

Sodium + Water → Sodium hydroxide + Hydrogen

The balanced equation for the following chemical reactions is given as :

Q 3. (i) Write a balanced chemical equation with state symbols for the following reactions.

Solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride.

The reaction of solutions of barium chloride and sodium sulphate in water react to give insoluble barium sulphate and the solution of sodium chloride is given by :

Q 3. (ii) Write a balanced chemical equation with state symbols for the following reactions.

Sodium hydroxide solution (in water) reacts with a hydrochloric acid solution (in water) to produce sodium chloride solution and water.

The reaction of sodium hydroxide solution (in water) reacts with a hydrochloric acid solution (in water) to produce sodium chloride solution and water is given by :

## Topic 1.2 Types of chemical reactions

Q 1. (i) A solution of a substance is used for whitewashing.

Name the substance ‘X’ and write its formula

The substance ‘X’ is calcium oxide and its formula is CaO.

Q 1.(ii) A solution of a substance is used for whitewashing.

Write the reaction of the substance named in (i) above with water

The reaction of calcium oxide with water is given by :

Q 2. Why is the amount of gas collected in one of the test tubes in Activity double of the amount collected in the other? Name this gas.

Water contains one part oxygen and two parts hydrogen. During electrolysis, oxygen and hydrogen are produced in a 1:2 ratio. In electrolysis oxygen goes in one test tube and hydrogen in a second test tube, so the amount of gas collected in the second test tube is double of first one.

NCERT textbook solutions for class 10 science chapter 1 Chemical Reaction and Equation

## Topic 1.3 Have you observed the effects of an oxidation reaction in everyday life?

Q 1. Why does the colour of copper sulphate solution change when an iron nail is dipped in it?

The color of copper sulphate solution change when an iron nail is dipped in it because iron displaces copper from copper sulphate forming iron sulphate,which is green.

The colour change from blue to green.

Q 2. Give an example of a double displacement reaction other than the one given in Activity.

An example of a double displacement reaction other than the one given in Activity is :

Q 3.(i) Identify the substances that are oxidized and the substances that are reduced in the following reactions.

In the above reaction, Na is oxidised and oxygen gets reduced.

Q 3.(ii) Identify the substances that are oxidized and the substances that are reduced in the following reactions.

In the above reaction, CuO is reduced to form Cu and hydrogen gets oxidized to water.

## Solutions for NCERT class 10 science chapter 1 Chemical Reactions and Equations- Exercise solutions

Q 1. Which of the statements about the reaction below are incorrect?

(a) Lead is getting reduced.

(b) Carbon dioxide is getting oxidized.

(c) Carbon is getting oxidized.

(d) Lead oxide is getting reduced.

(i) (a) and (b)

(ii) (a) and (c)

(iii) (a), (b) and (c)

(iv) all

In the above reaction, PbO reduces to Pb and C(carbon) gets oxidized to carbon dioxide.

Hence, statements (a) and (b) are correct.

Thus, option (i) is correct.

Q 2. The above reaction is an example of a

(a) combination reaction.

(b) double displacement reaction.

(c) decomposition reaction.

(d) displacement reaction

The above reaction is an example of a displacement reaction.

Hence, option (d) is correct.

Q 3. What happens when dilute hydrochloric acid is added to iron filings? Tick the correct answer.

(a) Hydrogen gas and iron chloride are produced.

(b) Chlorine gas and iron hydroxide are produced.

(c) No reaction takes place.

(d) Iron salt and water are produced.

When dilute hydrochloric acid is added to iron fillings then hydrogen gas and iron chloride are produced.

The reaction is given as :

Thus, option (a) is correct.

Q 4. What is a balanced chemical equation? Why should chemical equations be balanced?

The chemical equation which has an equal number of atoms of all elements on both sides of the reaction is known as a balanced chemical equation.

The law of conservation of mass states that mass can neither be created nor be destroyed so chemical equations should be balanced.

Q 5. (a) Translate the following statements into chemical equations and then balance them.

Hydrogen gas combines with nitrogen to form ammonia.

Hydrogen gas combines with nitrogen to form ammonia can be written as :

Q 5 (b) Hydrogen sulphide gas burns in air to give water and sulfur dioxide.

Hydrogen sulphide gas burns in air to give water and sulfur dioxide can be written as :

Q 5. (c) Barium chloride reacts with aluminum sulphate to give aluminum chloride and a precipitate of barium sulphate.

Barium chloride reacts with aluminum sulphate to give aluminum chloride and a precipitate of barium sulphate can be written as :

Q 5. (d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.

Potassium metal reacts with water to give potassium hydroxide and hydrogen gas is given by :

Q 6. (a) Balance the following chemical equations.

Balance the following chemical equations. (a)

The balanced chemical equation is given as :

Q 6. (b) Balance the following chemical equations.

The balanced chemical equation is given as :

Q 6. (c) Balance the following chemical equations.

The balanced chemical equation is given as :

Q 6. (d) Balance the following chemical equations.

A balanced chemical equation is given as :

Q 7. (a) Write the balanced chemical equations for the following reactions.

(a) Calcium hydroxide + Carbon dioxide → Calcium carbonate + Water

Calcium hydroxide + Carbon dioxide →Calcium carbonate + Water

The balanced chemical equations for the above reaction is given as :

Q 7. (b) Zinc + Silver nitrate → Zinc nitrate + Silver

Zinc + Silver nitrate → Zinc nitrate + Silver

The balanced chemical equation for the above reaction is given as :

Q 7. (c) Aluminium + Copper chloride → Aluminium chloride + Copper

Aluminium + Copper chloride → Aluminium chloride + Copper

The balanced chemical equation for the above reaction is given as :

Q 7. (d) Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride

Barium chloride + Potassium sulphate → Barium sulphate + Potassium chloride

The balanced chemical equation for the above reaction is given as :

Q 8. (a) Write the balanced chemical equation for the following and identify the type of reaction in each case.

(a) Potassium bromide(aq) + Barium iodide(aq) → Potassium iodide(aq) + Barium bromide(s)

Potassium bromide(aq) + Barium iodide(aq) → Potassium iodide(aq) + Barium bromide(s)

The balanced chemical equation for the above reaction is given as :

It is a double displacement reaction.

Q 8. (b) Zinc carbonate(s) → Zinc oxide(s) + Carbon dioxide(g)

Zinc carbonate(s) → Zinc oxide(s) + Carbon dioxide(g)

The balanced chemical equation for the above reaction is given by :

It is decomposition reaction.

Q 8. (c) Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g)

Hydrogen(g) + Chlorine(g) → Hydrogen chloride(g)

The balanced chemical equation for the above reaction is given by :

It is combination reaction.

Q 8. (d) Magnesium(s) + Hydrochloric acid(aq) → Magnesium chloride(aq) + Hydrogen(g)

Magnesium(s) + Hydrochloric acid(aq) → Magnesium chloride(aq) + Hydrogen(g)

The balanced chemical equation for the above reaction is given by :

It is displacement reaction.

Q 9. What does one mean by exothermic and endothermic reactions? Give examples.

Exothermic reactions: Reactions in which heat is given out along with the products are called exothermic reactions.

Example :

Endothermic reactions: Reactions in which energy is absorbed are known as endothermic reactions.

Example: The process of photosynthesis.

Q 10. Why is respiration considered an exothermic reaction? Explain .

We know that energy is required to support life. We get energy from the food we eat.

The large molecules of food are broken into a simpler substance like glucose during digestion.

Glucose and oxygen react to provide energy to the body. This reaction is a combination reaction named as respiration. In this whole process, energy is released so respiration is considered an exothermic reaction.

Q 11. Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.

In decomposition reactions, we can observe that a single reactant breaks down to give simpler products. This reaction source of energy. Whereas, in combination reaction two or more substances combine to give a product and energy is released in this reaction.

Hence, decomposition reactions called the opposite of combination reactions.

Example :

decomposition reaction :

and the combination reaction :

Q 12. Write one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.

The decomposition reaction by heat:

The decomposition reaction by light :

The decomposition reaction by electricity :

Q 13. What is the difference between displacement and double displacement reactions? Write equations for these reactions.

When an element displaces another element from its compound, a displacement reaction occurs.

Example :

Two different atoms or groups of atoms (ions) are exchanged in a double displacement reaction.

Example :

Q 14. In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved.

In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. The reaction involved can be written as :

Q 15. What do you mean by a precipitation reaction? Explain by giving examples.

Any reaction that produces a precipitate is called a precipitation reaction.

Example :

Here, we have as precipitate so it is a precipitation reaction.

Q 16.(a) Explain the following in terms of gain or loss of oxygen with two examples each.

Oxidation

Oxidation is a reaction in which the gain of oxygen or loss of hydrogen can be observed.

Example :

Q 16. (b) Reduction

The reaction in which the loss of oxygen or gain of hydrogen can be observed is known as reduction reaction.

Example :

Q 17. A shiny brown coloured element ‘X’ on heating in the air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.

A shiny brown colored element is copper (Cu) and on heating, in the air it becomes black in colour because of the formation of copper oxide(CuO).

Q 18. Why do we apply paint on iron articles?

To prevent iron from rusting paint is applied to iron articles. After applying paint iron articles are not in contact with moisture and air and hence rusting is prevented.

Q 19. Oil and fat containing food items are flushed with nitrogen. Why?

We know that nitrogen is an inert gas and does not react with the oil and fat-containing food. Whereas, other gases like oxygen react with the oil and fat-containing food and make them rancid. Hence, to remove oxygen and prevent food from acidity food items are flushed with nitrogen.

Q 20.(a) Explain the following terms with one example each.

Corrosion

Corrosion is a process in which metals deteriorate due to chemical reaction with moisture, air, and chemicals. Rusting of iron is a major example of corrosion. Iron corrodes in the presence of moisture and air.

Q 20. (b) Rancidity

(b) Rancidity

The process of oxidation of fats and oils which can be noticed by a change in color, smell, and taste is known as rancidity.

Example: When butter is kept in the open atmosphere than its smell and taste change which results in rancidity.

## Chapter-Wise NCERT Solutions for Class 10 Science

 Chapter No. Chapter Name Chapter 1 Chemical Reactions and Equations Chapter 2 Acids, Bases, and Salts Chapter 3 Metals and Non-metals Chapter 4 Carbon and Its Compounds Chapter 5 Periodic Classification of Elements Chapter 6 Life Processes Chapter 7 Control and Coordination Chapter 8 How do Organisms Reproduce? Chapter 9 Heredity and Evolution Chapter 10 Light Reflection and Refraction Chapter 11 The Human Eye and The Colorful World Chapter 12 Electricity Chapter 13 Magnetic Effects of Electric Current Chapter 14 Sources of Energy Chapter 15 Our Environment Chapter 16 Sustainable Management of Natural Resources

### Benefits of NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations

• Through NCERT Class 10 Science solutions chapter 1, you will also get to know why balancing in between chemical equations is important.

• The Class 10 Science Chapter 1 NCERT solutions an overview of the main concepts mentioned in the chapter and helps you to get well versed with important topics such as writing chemical equations and balancing them.

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### How to Use NCERT Solutions for Class 10 Science Chapter 1 Chemical Reactions and Equations?

• Firstly go through the chapter and learn all the concepts. Afterwards, move to the NCERT Class 10 Science Solutions Chapter 1.

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