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: Recall phase equilibrium condition.
During condensation, a substance changes from vapor to liquid, and properties like enthalpy, internal energy, and specific volume change.

Step 2: Gibbs free energy.
At equilibrium, the Gibbs free energy remains the same for both phases in equilibrium. Therefore, it does not change during condensation.

Step 3: Conclusion.
Hence, the correct answer is (D) Specific Gibbs energy.