What type of phenomenon is adsorption? What type of reaction is adsorption?

(N/A) Adsorption is a $surface$ phenomenon because it involves the accumulation of molecular species at the surface rather than in the bulk of a solid or liquid.
Adsorption is an $exothermic$ process. In this process,the residual forces of the surface are satisfied,leading to a decrease in surface energy,which is released as heat.