Which of the following is an example of an exothermic reaction?

An exothermic reaction is characterized by the release of energy, primarily in the form of heat, to the surroundings. Combustion is a classic example of an exothermic reaction where a substance, typically a hydrocarbon, reacts with oxygen, resulting in the formation of carbon dioxide and water, along with the release of a significant amount of heat and light. This release of energy is what makes combustion a practical and commonly utilized reaction in everyday applications, such as in engines and heating systems.

In contrast, photosynthesis is an endothermic process, as plants absorb energy from sunlight to convert carbon dioxide and water into glucose and oxygen. Thermal decomposition involves breaking down a compound into simpler substances, often requiring heat input, making it endothermic as well. The melting of ice is a physical change that absorbs heat from the surroundings, also classifying it as an endothermic reaction. Thus, combustion stands out as the correct choice among the options presented as it exemplifies the release of energy, making it an exothermic reaction.