What is cohesion in liquids?

• A. The attractive forces within a solid.
• B. The attractive forces between the molecules in a liquid, producing surface tension.
• C. The gravitational force acting on a liquid.
• D. The attractive forces between a liquid and a solid surface.

Answer: (B)

Cohesion refers to the internal attraction between molecules within a liquid. These cohesive forces pull the molecules toward one another, especially at the surface, where there are fewer neighboring molecules above. This inward pull creates surface tension—the “skin” on the liquid’s surface that makes droplets form and lets some creatures skim the surface. The description that focuses on the attractive forces between molecules in a liquid producing surface tension matches this concept perfectly. Gravitational force is the weight of the liquid, not a cohesive interaction. Attraction between the liquid and a solid surface is adhesion, not cohesion. And attraction within a solid describes cohesion in a solid, not a liquid.