Which term describes the process by which molecules cling to a surface rather than being absorbed into the bulk?

Which term describes the process by which molecules cling to a surface rather than being absorbed into the bulk?

• A. Absorption
• B. Adsorbent
• C. Adsorption
• D. Adsorbate

Answer: (C)

Adsorption is the process by which molecules adhere to a surface, forming a film at the boundary rather than entering the material’s interior. This surface attachment occurs because forces at the surface—such as van der Waals attractions or chemical bonding—pull the molecules toward the boundary. It’s different from absorption, where substances are taken into the bulk of a material. The surface that does the sticking is called the adsorbent, and the molecules being captured are the adsorbates. For example, activated carbon in a filter adsorbs organic molecules onto its surface rather than dissolving them into the carbon itself.

Adsorption is the process by which molecules adhere to a surface, forming a film at the boundary rather than entering the material’s interior. This surface attachment occurs because forces at the surface—such as van der Waals attractions or chemical bonding—pull the molecules toward the boundary. It’s different from absorption, where substances are taken into the bulk of a material. The surface that does the sticking is called the adsorbent, and the molecules being captured are the adsorbates. For example, activated carbon in a filter adsorbs organic molecules onto its surface rather than dissolving them into the carbon itself.