Question

what is exothermic reactions explain with example

Answer 1

Many chemical reactions absorb or release heat and energy as part of the process. An exothermic reaction is any reaction that releases or gives off energy during the reaction. You can remember this by putting together 'exo-' which means to exit, with 'therm' which refers to heat. example:- The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become hotter. ... Some examples of exothermic reactions are: Combustion (burning)

Answer 2

An exothermic reaction occurs when the temperature of a system increases due to the evolution of heat. This heat is released into the surroundings, resulting in an overall negative quantity for the heat of reaction (qrxn<0qrxn<0).
An endothermic reaction occurs when the temperature of an isolated system decreases while the surroundings of a non-isolated system gains heat. Endothermic reactions result in an overall positive heat of reaction (qrxn>0qrxn>0).

Examples of Exothermic Reactions

any combustion reaction

a neutralization reaction

rusting of iron (rust steel wool with vinegar)

the thermite reaction

reaction between water and calcium chloride

reaction between sodium sulfite and bleach (dilute sodium hypochlorite)

reaction between sodium and chlorine to make sodium chloride (table salt)

reaction between water and any strong acid

reaction between water and any anhydrous salt

dissolving laundry detergent in water