Question

Where does evaporation take place?

Answer 1

Hint : Evaporation takes place at a point where the thermal energy of the liquid is enough to overcome the surface tension that acts on the liquid and overcome the surrounding vapour pressure. Only the liquid molecules that can break their bonds with other liquid molecules can be considered as evaporated.

Complete step by step answer
Evaporation is a type of vaporization that takes place on the surface of a liquid when the liquid is heated. When the liquid is heated, the average kinetic molecules of the liquid molecules will rise. Then for molecules of the liquid near the surface of the liquid, molecules colliding can transfer their momentum to each other in such a way that a molecule can gain enough energy to overcome the attractive force it experiences with other liquid molecules. At this point, it will move away from the surface of the liquid and can be considered as evaporated.
Roughly, only a few molecules have enough energy to escape the surface of the liquid and be considered as evaporated. As the liquid evaporates, the thermal energy of the system is used to break the liquid molecule bonds and in providing kinetic energy to the escaped molecules. Hence the thermal energy of the liquid decreases when it is evaporated which is why we must keep on heating a liquid to keep on making it evaporate.

Note
For molecules that are situated inside the surface of the liquid, the intermolecular forces are strong enough that the thermal energy of the liquid will not be equal to break them. Evaporation can only occur till the point the pressure due to the vapours of the liquid matches the vapour pressure of the surrounding air.