Question

In a phase diagram, what does the critical point mean?

a) The point where all phases coexist

b) The highest temperature in the diagram

c) The point where gas and liquid phases become indistinguishable

d) The lowest temperature in the diagram

Answer 1

The critical point on a phase diagram is where the gas and liquid phases of a substance become indistinguishable and form a supercritical fluid.

Step-by-step explanation:

In a phase diagram, the critical point represents the combination of temperature and pressure beyond which the distinct gas and liquid phases of a substance become indistinguishable, forming a supercritical fluid. It is defined by a critical temperature (Tc), above which a substance can no longer exist in the liquid state, and a critical pressure (Pc), the minimum pressure required to liquefy a substance at its critical temperature. Thus, the correct answer to the question is c) The point where gas and liquid phases become indistinguishable.