Question

What is. an exothermic reaction

Answer 1

An exothermic reaction is a chemical reaction that releases energy by light or heat. It is the opposite of an endothermic reaction.[1]
Expressed in a chemical equation: reactants → products + energy. Exothermic Reaction means "exo" meaning releases and "thermic" means heat. So the reaction in which there is release of heat with or without light is called exothermic reaction.