Consider the phase diagram below: What changes would the sample undergo as the sample moves from the temperature and pressure at point 'a' to the temperature and pressure at point 'b'?

• A. gas to liquid
• B. solid to liquid
• C. solid to gas
• D. liquid to gas
• E. liquid to solid

Answer: (B)

Verified step by step guidance

1. Identify the regions on the phase diagram: The phase diagram is divided into regions representing solid, liquid, and gas phases. The lines separating these regions are the phase boundaries.
2. Locate point 'a' and point 'b' on the phase diagram: Point 'a' is at a lower temperature and pressure, while point 'b' is at a higher temperature and pressure.
3. Determine the phase at point 'a': Based on the position of point 'a' relative to the phase boundaries, identify whether it is in the solid, liquid, or gas region.
4. Determine the phase at point 'b': Similarly, identify the phase at point 'b' by its position relative to the phase boundaries.
5. Analyze the transition from point 'a' to point 'b': As the sample moves from point 'a' to point 'b', observe the path it takes across the phase boundaries to determine the phase changes involved.