Question

Enthalpy of sublimation of a substance is equal to ______.

Options

• Enthalpy of fusion + Enthalpy of vapourisation

• Enthalpy of fusion

• Enthalpy of vapourisation

• Twice the enthalpy of vapourisation

Answer 1

Enthalpy of sublimation of a substance is equal to enthalpy of fusion + enthalpy of vapourisation.

Explanation:

Sublimation is direct conversion of solid to vapour, i.e., solid → vapour

Writing in two steps, we have solid → liquid → vapour.

Solid → liquid requires enthalpy of fusion.

Liquid →vapour requires enthalpy of vapourisation