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



Energy is supplied in the form of heat;


Decomposition of Calcium Carbonate (CaCO 3

On heating of Calcium Carbonate (limestone),

It decomposes into Calcium Oxide (Quick Lime) + Carbon Dioxide


CaCO 3 (s)         →          CaO(s) + CO 2 (g) 

                                            (Limestone)    Heat       (Quick lime)

Energy is supplied in the form of light;


Silver Chloride turns grey in sunlight

It is because, the heat of sunlight decomposes silver chloride into silver and chlorine


2AgCl(s)      →      2Ag(s) + Cl 2 (g)


Energy is supplied in the form of electricity;


Electrolysis of water

The breaking down of H 2 O into H 2 and O 2 by passing electricity is known as electrolysis of water.

2H 2 O        →          2H 2 + O 2


  1. Class 10
  2. Chapter 1 Class 10 - Chemical Reactions and Equations (Term 1)

About the Author

CA Maninder Singh's photo - Founder at Teachoo
CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo