What do you understand by exothermic reaction and endothermic reaction? Give one example of each type.

Exothermic reactions Reactions which are accompanied by an evolution of heat are called exothermic reactions. The quantity of heat produced is shown along with the products with a '-' sign in terms of $△H$. For e.g,
$CaO\left(s\right)+C{O}_2\left(g\right)⟶CaC{O}_3\left(g\right)△H=-178.3KJ/mol$

Endothermic Reactions Reactions which proceeds with the absorption of heat are called endothermic reactions. The quantity of heat absorbed is shown either along with the products with a '+' sign in terms of $△H$. For e.g.,$2N{H}_3\left(g\right)⟶N_2\left(g\right)+3H_2\left(g\right)△H=+91.8$