Final answer:
The difference in molecules of a liquid with weaker surface tension than water is that they have weaker cohesive forces (option d) , unlike water's strong hydrogen bonds which create a higher surface tension.
Step-by-step explanation:
The student asked: Which of the following best describes the difference in the molecules of a liquid with weaker surface tension than water compared to water? The correct answer is: d) They have weaker cohesive forces.
Surface tension is directly related to the intermolecular forces present in a liquid. Liquids with strong intermolecular forces, like water which has hydrogen bonding, exhibit a high surface tension because these forces pull the surface molecules into the liquid, creating a 'skin' that is difficult to break. In contrast, a liquid with weaker intermolecular forces will have a weaker surface tension as there are lesser cohesive forces acting upon the molecules at the surface, making it easier to increase the liquid's surface area.