Question

The rise of a liquid in capillary tube is due to:
A. Viscosity
B. Osmosis
C. Diffusion
D. Surface tension

Answer 1

Hint: The capillary tube is a copper tube with a very small internal diameter. The rise of a liquid in the capillary tube is due to the surface tension. Adhesion of water to the walls of the capillary tube will lead to an upward force on the liquid at the edges. This turns the meniscus in an upward direction. The capillary rise of a liquid can be influenced by surface tension, the density of the liquid, the viscosity of the liquid, and the diameter of the capillary tube.

Complete step by step answer:
Viscosity is a measure of fluid's resistance to flow. The best example is when we pour oil and water into the ground, we find that water flows faster than oil. This is because oil is more viscous than oil. Thus, the rise of liquid in the capillary tube is not due to viscosity.
Osmosis is the process of passing the molecules of solvent from less concentrated to a high concentrated solution through a semi-permeable membrane. The rise of liquid in the capillary tube is not done through a semi-permeable membrane. It is a natural process.
Diffusion is the process of movement of particles from the area of higher concentration to lower concentration. In the rise of liquid in a capillary tube, it won't deal with concentration.
Surface tension is the cohesive force between liquid molecules and it is like the existence of intermolecular forces of attraction in liquid. The capillary action arises when the adhesive force of liquid is greater than the cohesive force between liquids and it will lead to a rise of liquid in the capillary tube.

So, the correct answer is Option D.

Note: The rise of liquid in the capillary tube is due to surface tension. This is because the adhesive force of liquid (Capillary action) is greater than the cohesive force between liquids (surface tension) and it will lead to a rise in the liquid in the capillary tube. Surface tension can normally be observed in our daily life. The best example is when the insects like spiders move towards the water, their legs tend to stick on the surface of the water instead of immersing in water which is due to surface tension.