In a Pourbaix diagram, what are the typical axes and what does the diagram reveal about a metal’s stability?

• A. The axes are pH and electrode potential; it shows stability regions and predominant species.
• B. The axes are temperature and pressure; it shows phase boundaries.
• C. The axes are time and current; it shows corrosion rate.
• D. The axes are diffusion coefficient and pH; it shows transport properties.

Answer: (A)