Question

The graph alongside represents a cooling curve for a substance being cooled from a higher temperature to a lower temperature.

What is the boiling point and freezing point of the substance?

Answer 1

From the given graph we can predict that

Boiling point of substance is ${150}^{o}C$ as the phase change from vapor to liquid takes at this temperature represented by the line $BC$.

Freezing point of substance is ${100}^{o}C$ as the phase change from liquid to solid takes at this temperature represented by the line $DE$.