Types of Chemical Reactions with Examples Class 10 | Complete Notes with Equations

In Class 10 Science, one of the most important chapters is Chemical Reactions and Equations. Almost every exam includes questions on this topic, and students often struggle to identify types of chemical reactions, write balanced equations, and give examples.

Many students get confused about the difference between combination, decomposition, displacement, and double displacement reactions. This post will clear doubts with definition, balanced equations, examples, daily life applications and exam questions.

What is a Chemical Reaction?

A chemical reaction is a process in which one or more substances change into new substances with different properties.

Reactants: - Reactants are the substances that take part in a chemical reaction and are written on the left side of the equation.

 

Product: Products are the new substances formed and written on the right side of the equation.

Signs that a chemical reaction occurs

    ·     Change in colour

    ·     Change in temperature

    ·     Formation of gas

    ·     Formation of precipitate

    ·     Change in state

     

    Example:

    

     2H₂ + O₂ →2H₂O

    Hydrogen and oxygen combine to form water (a new substance)

   Main Types of Chemical Reactions (Class 10)

    In Class 10, chemical reactions are classified into the following types

    1. Combination reaction

    2. Decomposition reaction

    3. Displacement reaction

    4. Double displacement reaction

    5. Neutralisation reaction

    6. Precipitation reaction

    7. Redox reaction

    8. Exothermic reaction

    9. Endothermic reaction

Combination reaction (Synthesis reaction)

Definition

A reaction in which two or more substances combine to form a single product.

General form

A+ B →AB

Examples of a combination reaction

 

(i) 2Mg + O₂ →2MgO

(ii)CaO + H₂O → Ca(OH)₂

(iii)2H₂ + O₂ 2H₂O

(iv) N₂ + 3H₂   2NH₃

Daily Life Example

Formation of slaked lime when quick lime reacts with water during whitewashing.

Decomposition reaction

Definition

A reaction in which a single compound breaks down into two or more simpler substances.

General form

AB →A + B

Types of Decomposition Reaction

Decomposition is mainly of three types on the basis of the energy required for it.

(i) Thermal decomposition (by heat)

(ii)Electrolytic decomposition (by electricity)

(iii)Photolytic decomposition (by light)

Examples of decomposition reaction

Thermal decomposition

CaCO₃ → CaO + CO₂

Electrolytic decomposition

Photolytic decomposition

  

Daily Life Example

The breaking of silver chloride in sunlight is used in black-and-white photography

Displacement reaction (Single Displacement)

Definition

A reaction in which a more reactive element displaces a less reactive element from its compound.

General form

A +BC →AC + B

Examples of a displacement reaction

 (i)Zn + CuSO₄  → ZnSO₄ + Cu

 (ii)Fe + CuSO₄  → FeSO₄ + Cu

(iii)Cu + 2AgNO₃ →Cu(NO₃)₂  +2Ag

Daily life example

Iron nails dipped in copper sulphate solution turn brown due to copper deposition.

Double Displacement Reaction

Definition

A reaction in which two compounds exchange their ions to form two new compounds.

General form

AB + CD → AD + CB

Examples

(i)Na₂SO₄ + BaCl₂ →BaSO₄ +2NaCl

(ii)AgNO₃ + NaCl →AgCl + NaNO₃

(iii)Pb (NO₃)₂ +2KI →PbI₂ + 2KNO₃

Daily life example

Formation of yellow precipitate of lead iodide in school experiments.

Neutralisation Reaction (Acid- Base reaction)

Definition

A chemical reaction in which an acid and a base react to form a salt and water.

General form

Acid + Base → Salt + Water

Examples

(i)HCl + NaOH →NaCl +H₂O

(ii)H₂SO₄ + 2KOH →K₂SO₄ +2H₂O

(iii)HNO₃ + NH₄OH→ NH₄NO₃ +H₂O

Daily life examples

    ·     Antacid neutralises excess acid in the stomach

    ·     Treatment of acidic soil using quick lime or slaked lime

    ·     Toothpaste neutralises acids in the mouth

Precipitation Reaction

Definition

A precipitation reaction is a reaction in which two aqueous solutions react to form an insoluble solid called a precipitate.

General form

AB _(aq) + CD _(aq) →AD_(s) ↓ + CB _(aq)

Examples

(i)AgNO_3(aq) + NaCl_(aq) →AgCl_(s)↓ + NaNO_3(aq)

(ii)Pb (NO₃)_2(aq) +2KI_(aq) →PbI_2(s) ↓+ 2KNO_3(aq)

(iii)Na₂SO_4(aq) + BaCl_2(aq) →BaSO_4(s) ↓+2NaCl_(aq)

Daily life/ lab example

Formation of yellow precipitate of lead iodide in school experiments.

Exothermic Reaction

Definition

A reaction in which heat is released during the reaction is called an exothermic reaction.

General form

AB + CD AD + CB + Heat

Examples

(i)CH₄ +2O₂ →CO₂ +2H₂O +Heat

(ii)CaO + H₂O →Ca(OH)₂ + Heat

(iii)Respiration in our body

Daily life examples

    ·     Burning of fuels

    ·     Respiration

    ·     Whitewashing walls 

Endothermic Reaction

Definition

A reaction in which heat is absorbed during the reaction is called an exothermic reaction.

General form

ABC + heat →AB + C

Examples

(i)       

 

 

 

Daily life example

Photosynthesis in green plants

 

Difference between Chemical Reactions

Reaction Type	Reactants	Products	Key Feature
Combination	Two or more substances	One substance	Substances combine to form a single product
Decomposition	One compound	Two or more substances	Complex substances break into simpler substances
Displacement	Element + compound	New compound + element	More reactive displaces less reactive
Double displacement	Two compounds	Two new compounds	Exchange of ions
Neutralisation reaction	Acid + Base	Salt + Water	Acids and bases neutralise each other
Precipitation reaction	Two aqueous solutions	Insoluble substance + aqueous solution	Formation of a solid substance
Redox reaction	Any substance	Any substance	Oxidation and reduction occur together
Exothermic reaction	Any substance	Any substance	Heat released
Endothermic reaction	Any substance	Any substance	Heat absorbed

 

 

Most Important Daily Life Chemical Reactions

    ·     Whitewashing walls

    ·     Rusting of iron

    ·     Burning of fuels

    ·     Digestion of food

    ·     Respiration

    ·     Photosynthesis 

    MCQs on Types of Chemical Reactions

Q1. A reaction in which two or more substances combine to form a single product is called:

(a)       Decomposition

(b)      Combination

(c)       Displacement

(d)      Redox

Correct answer – (b)      Combination

Q2.  CaCO₃ →CaO + CO₂ is an example of:

(a)       Combination

(b)      Decomposition

(c)       Displacement

(d)      Neutralisaiton

Correct answer - (b) Decomposition

Q3. Zn + CuSO₄  → ZnSO₄ + Cu  is:

(a)       Double displacement

(b)      Decomposition

(c)       Displacement

(d)      Combustion

Correct answer - (c) Displacement

Q4. Exchange of ions between two compounds is called:

(a)       Displacement

(b)      Combination

(c)       Double displacement

(d)      Redox

Correct answer - (c) Double displacement

Q5. Burning of methane in air is an example of:

(a)       Redox reaction

(b)      Combustion reaction

(c)       Decomposition reaction

(d)      Neutralization

Correct answer - (b) Combustion reaction

Q6. A reaction in which oxidation and reduction occur together is called:

(a)       Combination

(b)      Redox

(c)       Displacement

(d)      Neutralization

Correct answer - (b) Redox

Q7. HCl + NaOH →NaCl +H₂O is:

(a)       Combination reaction

(b)      Displacement reaction

(c)       Decomposition reaction

(d)      Neutralisation reaction

Correct answer - Neutralisation reaction

Q8. A reaction forming an insoluble solid from two solutions is:

(a)       Combination

(b)      Precipitation

(c)       Decomposition

(d)      Redox

Correct answer - (b) Precipitation

Q9. AgNO₃ + NaCl →AgCl + NaNO₃ is an example of:

(a)       Displacement reaction

(b)      Precipitation reaction

(c)       Combination reaction

(d)      Combustion reaction

Correct answer - (b) Precipitation reaction

Q10. A reaction in which heat is released is called:

(a)       Endothermic reaction

(b)      Exothermic reaction

(c) Neutralisation reaction

(d)      Displacement reaction

Correct answer - (b) Exothermic reaction

Q11. Photosynthesis is an example of:

(a)       Endothermic

(b)      Exothermic

(c)       Combustion

(d)      Redox

Correct answer - (a) Endothermic

Q12. CaO + H₂O → Ca(OH)₂ + Heat is:

(a)       Endothermic reaction

(b)      Displacement reaction

(c)       Exothermic reaction

(d)      Decomposition reaction

Correct answer - (c) Exothermic reaction

Q13. In a displacement reaction, the element that displaces another is:

(a)       Less reactive

(b)      More reactive

(c)       Non-metal

(d)      Neutral

Correct answer- (b) More reactive

Q14. Which of the following is a combination reaction?

(a)       2H₂ + O₂ →2H₂O

(b)      Zn + CuSO₄ →ZnSO₄ + Cu

(c)       CaCO₃ →CaO + CO₂

(d)      AgNO₃ + NaCl →AgCl + NaNO₃

        Correct answer - (a) 2H₂ + O₂ →2H₂O

Q15. Which reaction is used in whitewashing walls?

(a)       Decomposition

(b) Neutralisation

(c)       Combination

(d)      Displacement

Correct answer - (c) Combination

Q16. Rusting of iron is an example of:

(a)       Combination reaction

(b)      Redox reaction

(c)       Neutralization reaction

(d)      Precipitation reaction

Correct answer- (b) Redox reaction

Q17. Pb (NO3)2(aq) +2KI(aq) →PbI2(s) ↓+ 2KNO3(aq) is:

(a)       Displacement

(b)      Combination

(c)       Precipitation

(d)      Combustion

Correct answer - (c) Precipitation

Q18.  In a redox reaction, reduction means:

(a)       Gain of oxygen

(b)      Loss of oxygen

(c)       Gain of heat

(d)      Loss of water

Correct answer - (b) Loss of oxygen

Q19. Which of the following is an exothermic process?

(a)       Photosynthesis

(b)      Decomposition of CaCO₃

(c)       Respiration

(d)      Electrolysis of water

Correct answer - (c) Respiration

Q20. The new substances formed after a reaction are called:

(a)       Reactants

(b)      Elements

(c)       Substances

(d)      Products

Correct answer -  (d)      Products

Conclusion

After understanding the types of chemical reactions, you will be able to solve equations and exam questions very easily.

Frequently Asked Questions

Q1. Is every neutralisation reaction a double displacement reaction?

Answer

Yes, in a neutralisation reaction, an acid and a base exchange ions to form a salt and water, so it is a double displacement reaction.

Q2. What is the difference between exothermic and endothermic reactions?

Answer

Heat is released in exothermic reactions, and heat is absorbed in endothermic reactions.

Q3. What is a precipitation reaction?

Answer – In this reaction, two aqueous solutions react to produce an insoluble solid called a precipitate.