What term describes a metal that is less noble?

The term that describes a metal that is less noble is "anodic." In the context of electrochemistry and corrosion, metals are classified by their tendency to lose electrons. Noble metals, such as gold and platinum, resist oxidation and do not corrode easily; they are more noble. In contrast, less noble metals, like zinc or magnesium, tend to oxidize and lose electrons more readily, making them anodic.

When two dissimilar metals are placed in an electrolyte, the more noble metal acts as the cathode, while the less noble metal acts as the anode. This configuration leads to the anodic metal undergoing corrosion because it sacrifices itself to protect the cathodic metal from corroding. This principle is fundamental in practices such as cathodic protection and galvanic corrosion analysis.

The other terms refer to different aspects of the electrochemical process or do not directly describe the corrosion behavior of metals in the same way.