Question

Pressure – Temperature phase diagram of CO\(_2\) is shown below. Identify the correct phases from the given options. 
 

• A. I = Solid Phase, II = Liquid Phase, III = Gas Phase, IV = Supercritical Phase
• B. I = Gas Phase, II = Supercritical Phase, III = Solid Phase, IV = Liquid Phase
• C. I = Supercritical Phase, II = Liquid Phase, III = Solid Phase, IV = Gas Phase
• D. I = Gas Phase, II = Solid Phase, III = Liquid Phase, IV = Supercritical Phase

Hint:

In a phase diagram, the supercritical phase occurs above the critical point, where the substance behaves like both a gas and a liquid.

Answer 1

The Correct Option is D

The phase diagram of CO\(_2\) shows the relationship between pressure and temperature and indicates the different phases that CO\(_2\) can exist in, based on its state.
- Phase I (Gas Phase): The region where CO\(_2\) exists as a gas at lower pressures and temperatures.
- Phase II (Solid Phase): As the temperature decreases and pressure increases, CO\(_2\) transitions into a solid phase (dry ice).
- Phase III (Liquid Phase): When both pressure and temperature increase further, CO\(_2\) enters the liquid phase.
- Phase IV (Supercritical Phase): At pressures and temperatures above the critical point, CO\(_2\) enters the supercritical phase, where it has properties of both a gas and a liquid.
Thus, the correct identification of phases is:
- Phase I = Gas Phase
- Phase II = Solid Phase
- Phase III = Liquid Phase
- Phase IV = Supercritical Phase
Therefore, the correct answer is (D) I = Gas Phase, II = Solid Phase, III = Liquid Phase, IV = Supercritical Phase.