Final answer:
Greater surface tension in a liquid is determined by the strength of its intermolecular forces, with strong forces such as hydrogen bonding in water or metallic bonding in mercury leading to higher surface tensions.
Step-by-step explanation:
To ascertain which liquid has a greater surface tension, you must consider the strength of the intermolecular forces present within the liquids in question. The higher the energy required to increase the surface area of the liquid, the more significant its surface tension. Surface tension arises due to the cohesive forces between the molecules at the surface, which tends to pull the surface molecules into the bulk of the liquid, creating a tightened effect like a stretched membrane.
For example, water has a high surface tension because it exhibits strong hydrogen bonding between its molecules. Conversely, organic molecules with low-boiling points typically display much weaker intermolecular forces, thus having lower surface tensions. Anomalous cases like mercury have exceptionally high surface tension due to strong metallic bonding. Therefore, by comparing the nature of intermolecular forces and the respective energy per unit area measures, you can determine which liquid has the greater surface tension.