Question

Why is adsorption always exothermic?

Answer 1

The processes of bond formation or the formation of interaction between the molecules lead to the generation of energy which is released by the system itself. The energy which is released out of the system facilitates the other processes in the system proving the necessity of the generation of energy.

Complete step by step answer
Adsorption is a process in which one of the particles adhere to the surface of another medium, which is why there is an interaction between the adherent and surface which is similar to bond formation. In the process of bond formation energy is released and that is why it is considered an exothermic process. An exothermic process is a specific reaction in which the release of energy takes place at the end of the reaction. The molecules involved must have the specific chemical components which help it to interact with the surface.
The process of adsorption decreases the residual forces present on the surface taking part in adsorption. This condition decreases the energy of the surface which means the removal of energy takes place in the form of heat making the reaction exothermic. Some of the reactions take place on the surface or the adsorbate, which is why the adsorption process is important and a force of attraction is important to be present between the molecule and the surface keeping the molecule constantly associated.

Note
The reaction takes place on the surface of the adsorbate where in the presence of a force of attraction the action of chemical agents takes place. Since the bond formation occurs for the force of attraction, while the reaction the bond breakage can take place due to the process of reaction.