Enthalpy of sublimation of a substance is equal to :

Options

A. Enthalpy of fusion + enthalpy of vaporisation
B. Enthalpy of fusion
C. Enthalpy of vaporisation
D. Twice the enthalpy of vaporisation

Answer

A

Explanation

Enthalpy of sublimation of a substance is equal to enthalpy of fusion + enthalpy of vaporisation Sublimation is direct conversion of solid to vapour, solid `rarr` vapour
Writing in two step, we have solid `rarr` liquid `rarr` vapour
Solid `rarr` liquid requires enthalpy of fusion
Liquid `rarr` vapour requires enthalpy of vaporisation.