Which process describes swelling when immersed in water?

Which process describes swelling when immersed in water?

• A. Syneresis
• B. Imbibition
• C. Osmosis
• D. Diffusion

Answer: (B)

Swelling when a material is placed in water comes from imbibition. Water is taken up into a porous, hydrophilic solid or gel, and this absorption causes the structure to expand. The water binds to internal sites within the material through hydrogen bonding and capillary action, so the matrix increases in volume as it swells. This differs from osmosis, which is water moving across a semipermeable membrane from a region of lower solute concentration to higher solute concentration—often involving cells or membranes rather than a porous solid swelling. Diffusion is the general movement of molecules from high to low concentration, not tied to the swelling of a material. Syneresis is the opposite process: a gel contracts and squeezes out liquid. So the swelling observed when immersed in water is imbibition—the absorption of water by a hydrophilic material leading to expansion.

Swelling when a material is placed in water comes from imbibition. Water is taken up into a porous, hydrophilic solid or gel, and this absorption causes the structure to expand. The water binds to internal sites within the material through hydrogen bonding and capillary action, so the matrix increases in volume as it swells.

This differs from osmosis, which is water moving across a semipermeable membrane from a region of lower solute concentration to higher solute concentration—often involving cells or membranes rather than a porous solid swelling. Diffusion is the general movement of molecules from high to low concentration, not tied to the swelling of a material. Syneresis is the opposite process: a gel contracts and squeezes out liquid.

So the swelling observed when immersed in water is imbibition—the absorption of water by a hydrophilic material leading to expansion.