Question

Which statement is correct about the critical point of a phase diagram?

A. solid, liquid and gas are all present
B. liquid and gas are indistinguishable
C. liquid can be produced by a pressure change
D. gas can be produced by a temperature change

Answer 1

The correct statement about the critical point of a phase diagram is that liquid and gas phases are indistinguishable at this point, as they converge into a supercritical fluid.

Step-by-step explanation:

Among the statements provided about the critical point of a phase diagram, the correct one is that at the critical point, the liquid and gas phases are indistinguishable. In a phase diagram, the point known as the critical point marks the end of the vapor pressure curve of the liquid. Beyond this point, the substance cannot exist as a liquid regardless of the pressure and exists as a supercritical fluid, which is a phase where liquid and gas properties converge, and they can no longer be distinguished from one another. This is different from the triple point, where all three phases (solid, liquid, gas) coexist in equilibrium.