Which process is defined as the collection of gas molecules on solid surfaces?

The process defined as the collection of gas molecules on solid surfaces is adsorption. In this process, molecules of gas adhere to the surface of a solid material without penetrating into the bulk of the solid. This interaction typically involves weak intermolecular forces like Van der Waals forces, leading to a thin film of gas accumulating on the solid surface.

Adsorption is different from absorption, which involves the entire volume of the absorbing material, meaning that a substance is taken up by another substance and becomes part of it. Condensation and evaporation are processes related to changes in the state of matter, specifically involving the transition between gas and liquid phases. In contrast, adsorption specifically describes the interaction occurring at the interface between gases and solids, making it the correct answer to the question about the collection of gas molecules on solid surfaces.