What happens to energy during freezing?

• A. Energy is absorbed.
• B. Energy is released.
• C. Energy remains the same.
• D. Energy changes unpredictably.

Answer: (B)

Freezing releases energy. As a liquid becomes a solid, the molecules settle into a more ordered arrangement with lower potential energy, so energy must exit the system as heat to the surroundings. This release of latent heat of fusion makes the process exothermic. If heat is removed, the temperature can stay at the freezing point while the liquid turns into solid; once all liquid is solidified, further cooling can lower the temperature. The idea that energy is absorbed or stays the same doesn’t fit the phase-change behavior, and saying it changes unpredictably ignores the orderly, heat-releasing nature of solidification.