What property do colloidal substances exhibit that allows them to absorb large quantities of water?

The correct answer is imbibition, which refers to the process by which colloidal substances absorb large quantities of water, causing them to swell. This property is particularly crucial in various biological and physical processes. Colloids have a unique structural arrangement that allows them to interact effectively with water molecules, leading to the intake of water and the subsequent increase in volume.

In the context of colloidal substances, imbibition plays a significant role in hydration and swelling phenomena, as seen in the behavior of gels and certain types of clays. This capacity to absorb water affects their behavior in various applications, from agriculture to pharmaceuticals.

The other concepts listed—adsorption, diffusion, and precipitation—do not specifically address the ability of colloidal substances to absorb water in the same manner. Adsorption pertains to the adhesion of molecules to a surface, diffusion involves the movement of molecules from an area of higher concentration to an area of lower concentration, and precipitation refers to the formation of solid particles in a solution. Each of these processes has distinct characteristics and implications that do not directly apply to the absorption behavior represented by imbibition.