Question

the rate of evaporation of a liquid increases on heating explain

Answer 1

Evaporation basically means the surface liquid gets enough kinetic energy to change into gaseous state. Definition: when the surface pressure of a liquid is equal to the vapour pressure of the atmosphere, it evaporates.
When we heat a liquid, we give it energy, n hence, the (kinetic) energy of the liquid increases, (so consequently the kinetic energy of the surface liquid also increases.
As a result Rate of Evaporation increases

Answer 2

the rate of evaporation is directly proportional to temperature. it increase with the increase in temperature because of increase in kinetic energy of molecules.