Question

A liquid in a test tube has a curved surface such that the edges touching the glass are higher than the surface at the center. This must mean that the cohesive forces are less than the adhesive forces. True/False

Answer 1

True, a curved surface in a test tube indicating that the edges are higher than the center suggests stronger adhesive forces compared to cohesive forces, causing a concave meniscus.

Step-by-step explanation:

The statement that a liquid in a test tube has a curved surface with the edges touching the glass being higher than the surface at the center, suggesting that the cohesive forces are less than the adhesive forces, is True. This phenomenon is known as capillary action and can be observed when the adhesive forces between the liquid molecules and the surface of the tube are stronger than the cohesive forces within the liquid molecules themselves.

In such a case, the liquid wets the tube and the meniscus forms a concave shape. Conversely, if the cohesive forces were stronger, the meniscus would be convex.

Answer 2

False

Step-by-step explanation:

The cohesive forces of the liquid are greater than the adhesive forces hence the liquid is drawn inwards instead of spreading out. cohesion refers to the force of attraction between molecules of the same kind. it keeps molecules of the same kind together. It prevents the liquid from spreading out and wetting the glass hence the liquid will have a curved surface when in contact with the glass and this curved surface will be higher than the surface at the center. When the adhesive forces are greater, the curved surface will be lower than the surface at the center.