Question

For a pure substance, which of the following does not change during condensation?

• A. Specific volume
• B. Specific enthalpy
• C. Specific internal energy
• D. Specific Gibbs energy

Hint:

At equilibrium, the Gibbs free energy is the property that remains constant across different phases.

Answer 1

The Correct Option is D

Step 1: Phase Equilibrium.
Condensation involves a change from vapor to liquid, accompanied by alterations in enthalpy, internal energy, and specific volume.

Step 2: Gibbs Free Energy at Equilibrium.
At equilibrium, the Gibbs free energy is constant across coexisting phases. Consequently, it remains unchanged during condensation.

Step 3: Deduction.
Therefore, the correct option is (D) Specific Gibbs energy.