When does surface tension occur in liquids?

Surface tension in liquids occurs due to the attractive forces between molecules at the surface of the liquid. This phenomenon arises because molecules within the liquid experience intermolecular forces equally in all directions, while those at the surface are subjected to stronger attraction from the liquid molecules beneath them compared to those above, which are in contact with air. As a result, the surface molecules pull inward, creating a "film" effect that leads to the surface tension property.

This cohesive force at the surface is what allows certain objects, like a needle or a paperclip, to float on water despite being denser than the liquid, and it is also responsible for the shape of liquid droplets. The other options do not accurately describe the conditions under which surface tension occurs. For instance, surface tension is not directly related to uniform temperature, freezing point conditions, or atmospheric pressure. Instead, it is fundamentally based on the intermolecular forces acting on the surface molecules of the liquid.