Question

If the temperature of a saturated water is increased infinitesimally at constant entropy, the resulting state of water is:

• A. Liquid
• B. Liquid–vapor co-existence
• C. Saturated vapor
• D. Solid

Hint:

At constant entropy, heating saturated liquid leads to phase change into saturated vapor.

Answer 1

The Correct Option is C

Step 1: Recall phase equilibrium.
At saturation, water is at equilibrium between liquid and vapor. Increasing temperature at constant entropy implies a phase change.

Step 2: Entropy consideration.
Entropy remains constant (isentropic), so water transitions fully into saturated vapor.

Step 3: Conclusion.
Hence, the correct answer is (C) saturated vapor.