Types of Chemical Reactions

If we observe changes which are taking place around us such as changing of milk into curd, rusting of iron objects, digestion, cooking an egg etc. then we can come to know that a large variety of chemical reactions are taking place around us. In this article we will discuss various types of chemical reactions with a list of chemical reactions. 


What is Chemical Reaction? 

A chemical reaction is the process in which reactants react chemically and convert into products by chemical transformation. For example – Respiration – we inhale oxygen which reacts with glucose and produces carbon dioxide, water and energy. Reaction is given below – 

C6H12O6  +  6O2 🡪 6CO2 + 6H2O + Energy 


Characteristics of a Chemical Reaction 

Chemical reactions show one or more than one of the following characteristics –

  • Evolution of gas 

  • Change in color

  • Change in temperature 

  • Change in energy

  • Formation of precipitate 

  • Change in state 

Evolution of Gas – Some chemical reactions take place with the evolution of gas. For example, when zinc reacts with hydrochloric acid, hydrogen gas is evolved with formation of zinc chloride. 

Reaction - Zn + 2HCl 🡪 ZnCl2 + H2

Change in Color – Some chemical reactions are accompanied by a change in color. For example, when colorless lead nitrate reacts with potassium iodide it forms a yellow precipitate of lead iodide and colorless potassium nitrate. 

Reaction – Pb(NO3)         + 2KI          🡪                PbI2           +    2KNO3

                    Colorless      Colorless                     Yellow ppt      colorless

Change in Temperature – Some chemical reactions are accompanied by change in temperature. For example, some reactions are exothermic in nature while some are endothermic. 

Change in Energy – Chemical reactions often involve change in energy. During a chemical reaction, energy can be evolved or absorbed. For example, in combustion reactions energy is released such as burning of a fuel. 

Formation of Precipitate – Some chemical reactions are accompanied by formation of precipitate. For example, barium chloride reacts with sodium sulphate and forms sodium chloride and precipitate of barium sulfate.

Reaction – BaCl2 + Na2SO4 🡪    BaSO4           +        NaCl

                                                   Precipitate 

Change in State – Some chemical reactions are accompanied by change in state. For example, ammonia gas reacts with hydrogen chloride gas and forms solid ammonium chloride crystals. 

Reaction – NH3(g) + HCl(g) ↔️   NH4Cl(s)


Types of Chemical Reactions 

Chemical reactions are of many types. Here, we are covering most common eight types of chemical reactions which are part of class X chemistry syllabus as well. 

  • Decomposition reaction 

  • Combination reaction 

  • Combustion reaction 

  • Neutralization reaction 

  • Single displacement reaction 

  • Double displacement reaction 

  • Precipitation reaction 

  • Redox reaction 

Decomposition Reaction – In decomposition reaction, molecules or compounds break down into two or more than two simpler chemically new substances. For example, electrolysis of water. In electrolysis of water, water breaks down into hydrogen and oxygen which show completely different properties than water. 

Reaction - 2H2O electricity → 2H2 + O2

Combination Reaction – In combination reaction, two or more molecules are combined together chemically to form a new substance (compound). Combination and decomposition reactions are opposite of each other. For example, when we burn magnesium ribbon (or magnesium) it gives grey – black ash of magnesium oxide. 

Reaction – Mg + O2 🡪 MgO

Combustion Reaction – It is an exothermic reaction which releases energy, generally in the form of heat. It is a reaction between fuel and an oxidant (generally atmospheric oxygen) which produces smoke, water and heat generally.  For example, when we burn methane it gives carbon dioxide and water. 

Reaction – CH4 + 2O2 🡪 CO2 + 2H2O

Neutralization Reaction – In these reactions acid and base reacts with each other and form salt and water. For example, hydrochloric acid reacts with sodium hydroxide (base) and forms sodium chloride (salt) and water. 

Single Displacement Reaction – In these reactions more reactive metal displaces less reactive metal from its salt. In these reactions, products can be determined through reactivity series. Reactivity series is a series in which elements are arranged in decreasing order of their reactivity. It means the elements present at the top of this reactivity series are more reactive than the elements present at the bottom. 

Reaction of potassium with magnesium chloride is an example of single displacement reaction. In this reaction, potassium displaces magnesium from its salt because potassium is more reactive than magnesium. Potassium is present at the top of the reactivity series and is the most reactive element.

Reaction –  2K + MgCl2 🡪 2KCl + Mg

Double displacement reaction – In these reactions two aqueous ionic compounds exchange their ions (mostly cations) and produce two new compounds. For example potassium nitrate reacts with aluminum chloride and forms aluminum nitrate and potassium chloride. 

Reaction – KNO3 + AlCl3 🡪 Al(NO3)3 + KCl

Precipitation Reaction – In these reactions an insoluble precipitate is formed. In precipitation reactions, two soluble salts in aqueous solutions are combined and form an insoluble precipitate.  

Reaction – AgNO3(aq) + KCl(aq)🡪 AgCl + KNO3(aq)

Redox Reaction – Those chemical reactions in which oxidation and reduction take place simultaneously are called redox reactions. Oxidation is the addition of oxygen while reduction is the addition of hydrogen (or removal of oxygen). We have already discussed oxidation and reduction in a separate article with the title ‘Oxidation and Reduction’. You can refer to this article for detailed explanation of oxidation and reduction. 

Reaction of copper oxide with hydrogen is an example of redox reaction. In this reaction hydrogen has undergone oxidation by gaining oxygen atom while copper oxide has undergone reduction by removing oxygen. 

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We are giving here a general list of common chemical reactions –


List of Common Chemical Reactions

S.No.

Chemical reaction 

Equation 


Electrolysis of water 

2H2O electricity→ 2H2 + O2


Rusting of iron 

4Fe + 3O2 🡪 2Fe2O3


Reaction of quicklime (CaO) with water 

CaO + H2O 🡪 Ca(OH)2

Ca(OH)2 is known as slaked lime. 


Photosynthesis 

6CO2 + 6H2O 🡪 C6H12O6 + 6O2  (reaction takes place in presence of sunlight and chlorophyll)


Respiration 

C6H12O6 + 6O2 🡪 6CO2 + 6H2O


Combustion of hydrogen – Reaction of hydrogen gas with pure hydrogen. This is an exothermic reaction. 

2H2 + O2 🡪 2H2O + energy


Decomposition of FeSO4

2FeSO4 +heat 🡪 Fe2O3(s) + SO2(g) + SO3(g)

(Fe2O3(s) is green in color)


Decomposition of lead nitrate – In this reaction brown fumes of nitrogen dioxide gas are formed with yellow colored residue of lead oxide. 

2Pb(NO3)2 🡪 2PbO + 4NO2 + O2


Displacement reaction of iron and copper sulfate – Iron is more reactive than copper so it displaces copper from its salt and produces iron sulfate. 

Fe + CuSO4 🡪 FeSO4 + Cu


This ends our coverage on A list of Various Types of Chemical Reactions. We hope you enjoyed learning and were able to grasp the concepts. We hope after reading this article you will be able to differentiate various reactions easily and it will help you in experiments as well because we have covered almost all-important chemical reactions of Class X Chemistry Experiments. If you are looking for solutions to NCERT Textbook problems based on this topic, then log on to Vedantu website or download Vedantu Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Revision notes, Mock Tests and much more.