The point in the phase diagram where the fusion curve, the vapor pressure curve, and the sublimation curve join is called the
A) critical point.
B) triple point.
C) melting point.
D) boiling point.
E) double point.

Question

Quizplus · Accepted Answer

The point where the fusion curve, the vapor pressure curve, and the sublimation curve join is called the triple point. At this point, all three phases (solid, liquid, and gas) coexist in equilibrium. The triple point is a unique point on a phase diagram because any change in temperature or pressure will cause one of the phases to dominate over the other two. Therefore, the triple point is an important point of reference on a phase diagram.

The Point in the Phase Diagram Where the Fusion Curve