What is the term for the temperature at which a liquid is transformed into vapor?

The correct term for the temperature at which a liquid is transformed into vapor is the boiling point. This is a specific physical property of a substance where, under a given atmospheric pressure, a liquid turns into its gaseous form.

When a liquid reaches this temperature, its vapor pressure equals the external pressure surrounding the liquid, resulting in the formation of bubbles within the liquid that rise and release vapor into the atmosphere. This process is critical in various applications, including cooking, distillation, and understanding weather patterns.

The other terms listed refer to different phase changes: the freezing point is the temperature where liquid turns into solid, the melting point is the temperature where solid turns into liquid, and while evaporation can occur at any temperature, it does not refer to a specific temperature at which all of the liquid turns to vapor as boiling does. Hence, boiling point is the most accurate choice for this definition.