When a liquid is heated, the kinetic energy of its molecules increases in other words the temperature increases as well as the rate of vaporization increases.
When the kinetic energy of the molecules becomes maximum i.e., boiling point is reached any further heating at this stage will not increase the temperature rather heat will only be utilized to break the intermolecular forces and convert the liquid into vapour. “The amount of heat required to vaporization one mole of a liquid at its boiling point is its molar heat of vaporization. It is 40.6 kJ mole for water”.
