Question

Do all molecules of a liquid take part in evaporation? If not, explain your answer. $\left[3\text{Marks}\right]$

Answer 1

No, not all molecules of liquid take part in evaporation. Only those molecules near the surface take part in evaporation. $\left[1\text{Mark}\right]$

Explanation
The molecular force of attraction is less in liquids which makes the liquid molecules move throughout the liquid. During the random motion of particles, they collide, and some molecules gain, and some molecules lose energy. Particles near the surface which have energy to overcome the cohesive forces within the liquid, can escape from the bulk of the liquid. The escaping particles from the surface cause evaporation. $\left[2\text{Marks}\right]$