Question

What is the decomposition reaction? Explain it with suitable examples.

Answer 1

Hint: It is a type of reaction, in which the reactant is broken by the breaking of the bonds and forms two or more than two products. There are three types of a decomposition reaction. It is useful in analytical techniques.

Complete answer:
-A decomposition reaction is also known as chemical decomposition or chemical breakdown.
-It is a type of reaction in which the single reactant molecule breaks down into two or more compounds in the presence of heat, light, acidity, humidity, etc.
-This reaction always needs some energy to break the bonds which show that most of the reaction is endothermic whereas some reactions are exothermic such as the decomposition of ozone.
-For example, when decomposition of carbonic acid is done which is present in the soft drinks then it gives water and carbon dioxide.
\[{{\text{H}}_{2}}\text{C}{{\text{O}}_{3}}\ \to \text{ }{{\text{H}}_{2}}\text{O + C}{{\text{O}}_{2}}\]
- There are three types of decomposition reaction i.e. thermal, photolytic and electrolytic decomposition reaction.
-The thermal reaction is that reaction in which the energy is required to break the bonds.
For example, the decomposition of calcium carbonate i.e.
$\text{CaC}{{\text{O}}_{3}}\text{ }\xrightarrow{Heat}\ \text{CaO + C}{{\text{O}}_{2}}$
-The electrolytic reaction is that reaction which requires electric current to carry the reaction.
For example, electrolysis of water: $2{{\text{H}}_{2}}{{\text{O}}_{\left( \text{l} \right)}}\text{ }\to \text{ 2}{{\text{H}}_{2}}\text{ + }{{\text{O}}_{2}}$
-Photochemical reactions are those which take place in the presence of light.
For example, $\text{2AgC}{{\text{l}}_{\left( \text{s} \right)}}\text{ + sunlight }\to \text{ 2Ag + C}{{\text{l}}_{2}}\text{ }$
Applications: Decomposition reactions are used in the metal extraction from their ores such as the extraction of zinc from calamine.
-It can also be used in the synthesis of cement or calcium oxide.
-It is used in the welding process

Note: There is another decomposition reaction present in which the two molecules interchange their positive and negative with each other and form product i.e. AB +CD → AC +BD and the reaction is known as a double displacement reaction.