Types of Chemical Reactions Class 10 Science – Practice Questions with Answers

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Last Updated on July 25, 2025 by XAM CONTENT

Chemical reactions are a fundamental part of chemistry and everyday life. In Class 10 Science, understanding the types of chemical reactions helps you not only score well in exams but also build a strong foundation for advanced learning.

In this post, we provide a brief explanation, followed by 10 exam-relevant practice questions on types of reactions with detailed solutions, based on the latest CBSE Class 10 Science syllabus.

Types of Chemical Reactions – Class 10 Science

Understanding the different types of chemical reactions is a key concept in Class 10 Science. These reactions show how substances interact and change, and practicing problems can help reinforce your learning.

Quick Overview

CBSE Class 10 Science categorizes chemical reactions into the following types:

1. Combination Reaction – Two or more substances combine to form a single product.
2. Decomposition Reaction – A single compound breaks into two or more simpler substances.
3. Displacement Reaction – A more reactive element displaces a less reactive element from its compound.
4. Double Displacement Reaction – Exchange of ions between two compounds to form new compounds.
5. Redox Reaction – A reaction in which oxidation and reduction occur simultaneously.
6. Precipitation Reaction – Formation of an insoluble solid (precipitate) in a double displacement reaction.

Types of Chemical Reaction with examples

1. Combination Reaction

• Definition: Two or more substances combine to form a single product.
• General Form:
\[ A + B \rightarrow AB \]
• Example:
\[ \mathrm{C} + \mathrm{O}_2 \rightarrow \mathrm{CO}_2 \]

2. Decomposition Reaction

• Definition: A single compound breaks down into two or more simpler substances.
• General Form:
\[ AB \rightarrow A + B \]
• Example:
\[ 2\mathrm{H}_2\mathrm{O}_2 \rightarrow 2\mathrm{H}_2\mathrm{O} + \mathrm{O}_2 \]

3. Displacement Reaction

• Definition: An element replaces another element in a compound.
• General Form:
\[ A + BC \rightarrow AC + B \]
• Example:
\[ \mathrm{Zn} + \mathrm{CuSO}_4 \rightarrow \mathrm{ZnSO}_4 + \mathrm{Cu} \]

4. Double Displacement Reaction

• Definition: Two compounds exchange ions to form two new compounds.
• General Form:
\[ AB + CD \rightarrow AD + CB \]
• Example:
\[ \mathrm{Na}_2\mathrm{SO}_4 + \mathrm{BaCl}_2 \rightarrow \mathrm{BaSO}_4 + 2\mathrm{NaCl} \]

5. Redox Reaction

• Definition: A reaction involving oxidation (loss of electrons) and reduction (gain of electrons).
• Example:
\[ \mathrm{Fe}_2\mathrm{O}_3 + 2\mathrm{Al} \rightarrow 2\mathrm{Fe} + \mathrm{Al}_2\mathrm{O}_3 \]

6. Precipitation Reaction

• Definition: A reaction in which an insoluble solid (precipitate) is formed when two solutions are mixed.
• Example:
\[ \mathrm{AgNO}_3 + \mathrm{NaCl} \rightarrow \mathrm{AgCl} \downarrow + \mathrm{NaNO}_3 \]

7. Exothermic and Endothermic Reactions

• Exothermic: Reactions that release heat.
\[ \mathrm{C} + \mathrm{O}_2 \rightarrow \mathrm{CO}_2 + \text{Heat} \]
• Endothermic: Reactions that absorb heat.
\[ \mathrm{N}_2 + \mathrm{O}_2 \rightarrow 2\mathrm{NO} \quad \text{(requires energy)} \]

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Practice Questions on Types of Chemical Reactions

Practice Questions

1. Give one example each of a combination and a decomposition reaction.
2. Identify the type of reaction for each:
   \[ \text{a) } \mathrm{Na}_2\mathrm{CO}_3 + 2\mathrm{HCl} \rightarrow 2\mathrm{NaCl} + \mathrm{CO}_2 + \mathrm{H}_2\mathrm{O} \]
   \[ \text{b) } 2\mathrm{KBr} + \mathrm{Cl}_2 \rightarrow 2\mathrm{KCl} + \mathrm{Br}_2 \]
   \[ \text{c) } \mathrm{AgNO}_3 + \mathrm{NaCl} \rightarrow \mathrm{AgCl} \downarrow + \mathrm{NaNO}_3 \]
3. What is meant by a displacement reaction? Give an example.
4. Write the balanced chemical equation for the reaction when barium chloride and sodium sulphate react, and name the type of reaction.
5. Is rusting of iron an oxidation or reduction? Explain with equation.
6. Classify the reactions below as combination, decomposition, displacement, or double displacement:
   \[ \text{a) } \mathrm{Zn} + \mathrm{H}_2\mathrm{SO}_4 \rightarrow \mathrm{ZnSO}_4 + \mathrm{H}_2 \]
   \[ \text{b) } 2\mathrm{KClO}_3 \rightarrow 2\mathrm{KCl} + 3\mathrm{O}_2 \]
7. Write an example of a reaction that is simultaneously endothermic and decomposition.
8. Balance and identify the type of the reaction:
   \[ \mathrm{Fe} + \mathrm{CuSO}_4 \rightarrow \mathrm{FeSO}_4 + \mathrm{Cu} \]
9. Why is photosynthesis considered endothermic? Write the balanced equation.
10. Balance the reaction and identify the type:
    \[ \mathrm{CaO} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{Ca(OH)}_2 \]

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Answers

1. Combination:
   \[ \mathrm{N}_2 + 3\mathrm{H}_2 \rightarrow 2\mathrm{NH}_3 \]
   Decomposition:
   \[ 2\mathrm{H}_2\mathrm{O}_2 \rightarrow 2\mathrm{H}_2\mathrm{O} + \mathrm{O}_2 \]
2. a) Double displacement
   b) Displacement
   c) Precipitation (a type of double displacement)
3. A reaction in which a more reactive element displaces a less reactive element from its compound.
   Example:
   \[ \mathrm{Zn} + \mathrm{CuSO}_4 \rightarrow \mathrm{ZnSO}_4 + \mathrm{Cu} \]
4. \[ \mathrm{BaCl}_2 + \mathrm{Na}_2\mathrm{SO}_4 \rightarrow \mathrm{BaSO}_4 \downarrow + 2\mathrm{NaCl} \]
   This is a double displacement and precipitation reaction.
5. Rusting is an oxidation reaction where iron reacts with oxygen to form iron oxide:
   \[ 4\mathrm{Fe} + 3\mathrm{O}_2 \rightarrow 2\mathrm{Fe}_2\mathrm{O}_3 \]
6. a) Displacement reaction
   b) Decomposition reaction
7. Thermal decomposition of calcium carbonate — an endothermic and decomposition reaction:
   \[ \mathrm{CaCO}_3 \xrightarrow{\Delta} \mathrm{CaO} + \mathrm{CO}_2 \]
8. Balanced as given, type: Displacement reaction.
   \[ \mathrm{Fe} + \mathrm{CuSO}_4 \rightarrow \mathrm{FeSO}_4 + \mathrm{Cu} \]
9. Photosynthesis is endothermic because it absorbs sunlight energy:
   \[ 6\mathrm{CO}_2 + 6\mathrm{H}_2\mathrm{O} \xrightarrow{\text{sunlight}} \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\mathrm{O}_2 \]
10. Balanced combination reaction:
    \[ \mathrm{CaO} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{Ca(OH)}_2 \]

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Detailed Explanations for Select Answers

1. Combination and Decomposition Examples

Combination: Nitrogen and hydrogen combine to form ammonia.

Decomposition: Hydrogen peroxide decomposes into water and oxygen.

2. Reaction Identification

a) Double displacement because ions exchange places.

b) Displacement because chlorine displaces bromine.

c) Precipitation as an insoluble solid AgCl forms.

4. Precipitation Reaction

Barium sulfate forms as white precipitate when barium chloride reacts with sodium sulfate:

5. Rusting as Oxidation

Iron atoms lose electrons to oxygen forming iron oxide.

7. Endothermic Decomposition

Calcium carbonate decomposes upon heating absorbing energy:

9. Photosynthesis as Endothermic

Plants absorb sunlight to produce glucose and oxygen:

Frequently Asked Questions (FAQs) on Types of Chemical Reactions Class 10 Science