Question

Capillary action of the liquid can be explained on the basis of its:
(A) resistance to flow
(B) surface tension
(C) heat of vaporization
(D) refractive index

Answer 1

Hint: Think about what happens during capillary action. Try to remember what happens when you dip a capillary or pipette in any liquid. Then relate the concepts given in the options to get the answer.

Complete step by step solution:
- Capillary action is the movement of liquid in narrow spaces where there is zero opposition from external forces acting on it.
- For example, when a capillary tube is immersed in water, water level inside the capillary tube rises against the action of gravitational force.
-Surface tension is the force acting per unit length perpendicular to the line drawn on the surface of liquid.
- When water is kept in an open beaker. The molecules present in the bottom experience force of attraction from all sides because those molecules are surrounded on all sides by water molecules. The molecules present on the surface of the liquid have molecules present only below it, so they experience a downward force of attraction towards the bulk of the liquid. There is no force of attraction in the upward direction. Therefore, the surface of liquid is always under tension and behaves like a stretched membrane and tends to contract.
-The property of capillary action is due to this surface tension due to which the liquid rises or even sinks in the capillary.
-Therefore, capillary action of the liquid can be explained on the basis of its surface tension.

Hence, the answer is option (B).

Note: Remember surface tension causes capillary action. Surface tension decreases with rise in temperature. Soaps and detergents also work on reducing the surface tension of water.