The energy required to convert one mole of a liquid into vapour at its boiling point is called the

Explanation

Molar heat of vaporisation measures the energy needed to overcome the intermolecular forces completely, so it is large for hydrogen bonded liquids such as water at about 40.7 kJ per mole. Heat of fusion is the smaller quantity needed to melt a solid, because melting loosens the lattice without separating the particles. Neither is related to lattice energy, which concerns ionic solids.