What are cohesive and adhesive forces? How do these govern the wetting and
non-wetting properties of liquids?
Answers
Answer: Cohesive forces are the forces between the same types of molecules and Adhesive forces are the forces between the different types of molecules.
For wetting part try to understand what actually happens if a liquid is in capillary tube and its adhesive forces with material of capillary tube are stronger as compared to Cohesive forces then the liquid will tend to attach with the material of the capillary tube and hence we say that the liquid wets the capillary tube but if the Cohesive forces are stronger then the liquid will not tend to attach with the capillary tube walls and hence will not wet the capillary tube.
Answer:
Cohesion is the property of like molecules to stick with each other.
Adhesion is the property of different molecules to stick with each other.
When a liquid comes into contact with a surface, both forces will act on it.
Wetting:
Due to the effects of adhesive forces, liquid on a surface can spread out to form a thin uniform layer with a process known as wetting.