Two test tubes X and Y are filled with water and mercury, respectively. After these two liquids were poured, water drops on the inner walls of X were observed but no mercury drops in Y were seen. Give reasons.

Explanation

In between water molecules and glass molecules, adhesive forces continually act which are predominant over cohesive forces and hence water droplets are observed on the inner walls of the glass tube X. In case of mercury cohesive forces are more than adhesive forces and hence mercury, droplets are not observed on the inner walls of 'Y'.