Answer:
In which energy is released
Step-by-step explanation:
All those chemical reactions in which energy is released in some form is called exothermic. The energy is usually released as light or heat.
Chemically, an exothermic reaction can be represented as
reactants → products + energy.
Usually in a chemical reaction bonds between the molecules or atoms are either broken down or new bonds are re-established. In case of establishing new bond, energy is always released.
Some common examples of exothermic reactions are
a) Combustion of any fuel or gas
b) Rusting
c) Reaction between water and calcium chloride etc.