In a phase diagram for water, what is the name of the point at which water changes from a liquid to a solid?

• A. Boiling point
• B. Triple point
• C. Freezing point
• D. Critical point

Answer: (C)

Verified step by step guidance

1. Understand that a phase diagram shows the states of a substance (solid, liquid, gas) under different conditions of temperature and pressure.
2. Identify the point where water changes from liquid to solid, which corresponds to the temperature at which freezing or melting occurs under a given pressure.
3. Recognize that the 'Freezing point' is the temperature at which liquid water turns into solid ice at standard pressure.
4. Note that the 'Boiling point' is where liquid changes to gas, the 'Triple point' is where solid, liquid, and gas phases coexist, and the 'Critical point' is where liquid and gas phases become indistinguishable.
5. Conclude that the correct term for the transition from liquid to solid in the phase diagram is the 'Freezing point'.