What happens to the temperature of a liquid as it evaporates?

• A. The temperature of the liquid remains constant.
• B. The temperature of the liquid decreases.
• C. The temperature of the liquid increases.
• D. The temperature of the liquid fluctuates randomly.

Answer: (B)

Verified step by step guidance

1. Understand that evaporation is a phase change where molecules at the surface of a liquid gain enough energy to become gas.
2. Recognize that the molecules with the highest kinetic energy escape first during evaporation, which means the average kinetic energy of the remaining liquid molecules decreases.
3. Recall that temperature is a measure of the average kinetic energy of molecules in a substance.
4. Conclude that since the average kinetic energy of the liquid molecules decreases, the temperature of the liquid decreases during evaporation.
5. Note that this cooling effect continues as long as evaporation occurs and no external heat is added to the liquid.