Question

why is latent heat of vapourization higher than latent heat of fusion?

Answer 1

Latent heat is the heat required to convert a substance in liquid to gaseous state latent heat of fusion is the heat necessary to convert a substance from solid to liquid state. Latent heat of vaporization is always higher than the latent heat of fusion because there exist much more energy in the gases per unit mass than liquids. So to convert a unit mass of solid to liquid needs less energy compared to the conversion of a unit mass of liquid in to gas.