Which equation represents a decomposition reaction?

Which equation represents a decomposition reaction?

• A. C + H + O --> H2O + CO2
• B. AB + CD --> AD + CB
• C. A + B --> AB
• D. AB --> A + B

Answer: (D)

A decomposition reaction is when a single substance breaks down into two or more simpler substances. The equation AB → A + B is exactly that: AB splits into A and B, showing one reactant yielding two products. The other scenarios illustrate different processes: C + H + O forming H2O and CO2 uses smaller pieces to build more complex products, a synthesis/combination; AB + CD → AD + CB shows a swap of partners between two compounds, a double displacement; and A + B → AB is the formation of a compound from simpler pieces, another synthesis. So the equation AB → A + B cleanly represents decomposition.

A decomposition reaction is when a single substance breaks down into two or more simpler substances. The equation AB → A + B is exactly that: AB splits into A and B, showing one reactant yielding two products. The other scenarios illustrate different processes: C + H + O forming H2O and CO2 uses smaller pieces to build more complex products, a synthesis/combination; AB + CD → AD + CB shows a swap of partners between two compounds, a double displacement; and A + B → AB is the formation of a compound from simpler pieces, another synthesis. So the equation AB → A + B cleanly represents decomposition.