What is decomposition reaction? Explain with example.

A decomposition reaction is a chemical reaction in which one single compound splits into multiple simpler substances under suitable conditions.
Carbonic acid (H₂CO₃) is an ingredient of soft drinks. When carbonic acid breaks down to produce water (H₂O) and carbon dioxide (CO₂),  a decomposition reaction takes place. Therefore when we open a can of soft drink some of the carbon dioxides fizzes out.
The equation for this reaction is:
                                            H₂CO₃ --------> H₂O + CO₂