Liquids can interact with flat surfaces just as they can with capillary tubes; the cohesive forces within the liquid can be stronger or weaker than the adhesive forces between liquid and surface:

(b) Which of these diagrams, i or ii, rep- resents what happens when water is on a nonpolar surface?

Video transcript

Hey everyone, we're asked to consider the following diagrams and to identify the diagram that represents the interaction between a polar liquid and a non polar surface. Now, when we go ahead and predict this drawing, we have our non polar surface right here and when we create our polar liquid, we've learned that like attracts like so our polar molecules will be more attracted to one another, and that's because the cohesive forces within our liquid are much stronger than the adhesive forces between our liquid and our surface. So this is what essentially prevents that polar liquid from spreading. And comparing our drawing to the diagram, it looks like our first diagram is going to be our answer. Now, I hope that made sense and let us know if you have any questions.