Question

Which of the following does not represent enthalpy change during phase transformation?

• A. Standard enthalpy of fusion
• B. Standard enthalpy of vaporisation
• C. Standard enthalpy of sublimation
• D. Standard enthalpy of formation

Answer 1

Answer: (D)

Standard enthalpy of formation

Enthalpy of formation is the heat change when one mole of compound is obtained from its constituent elements. Thus, it does not represent enthalpy change during phase transformation.

While enthalpy of fusion, vapourization and sublimation represents enthalpy change during transformation from solid to liquid, liquid to gas and solid to gas respectively.