Question

(a) it is said that evaporation causes cooling, why? (b) explain how rate of evaporation of an aqueous solution decreases with incrase in humidity of surrounding air. (c) why do we see water droplets on the outer surface of glass containing ice cold water?

Answer 1

Evaporation takes away latent heat of the surface from which it evaporates.
When the air is humid, it contains lot of vapor , and cant take more vapor from evaporation, so it is slow when air is humid.