Water exhibits a concave meniscus in a glass tube whereas mercury exhibits the convex meniscus.
Answers
Answer:
When liquid water is confined in a tube, its surface (meniscus) has a concave shape because water wets the surface and creeps up the side. Mercury does not wet glass - the cohesive forces within the drops are stronger than the adhesive forces between the drops and glass.
Explanation:
Meniscus is a curve in the surface of a molecular substance and is produced in response to the surface of the container or another object. It can be either concave or convex. (please refer to the attached image)
Formation of meniscus depends on cohesive and adhesive forces in a liquid. For water, adhesive forces are stronger than the cohesive forces, therefore, water in a container stick to the wall of container and owing to the capillary action rises a little bit and form concave meniscus.
On the other hand, for mercury cohesive forces are stronger as compared to adhesive forces. Therefore, due to the capillary action the mercury falls down from the sides attached to the wall of the container and a convex or upward meniscus is obtained.