Question

Capillary depression, what will the angle of contact between the mercury and glass tube

Answer 1

capillarty means the tube of very fine bore is called capillary tube

Answer 2

Answer:

Mercury causes capillary depression because the intramolecular force in mercury molecules (cohesive force) is greater than that of the intermolecular force between mercury and glass molecules (adhesive force).

The angle of contact of mercury with glass will be obtuse angle.

Explanation:

It is the depression of the meniscus of the liquid present in the tube as it does not moisten the walls of the container.

The angle of contact between mercury and glass tube is approximately 135°.

When liquid and solid are in contact with each other, surface phases are formed which are solid-liquid, solid-air and liquid-air. The surface tension of all these tree surfaces can be denoted as Tsl, Tsa, Tla.

In case of, mercury-glass Tsa ≤ Tsl, where cos angle will be negative and the angle of contact will be obtuse angle.