The further an anode is away from a cathode on the galvanic series the ________ the damage.

• A. Lesser
• B. No change
• C. Greater
• D. Variable

Answer: (C)

Dissimilar metals in electrical contact in an electrolyte form a galvanic cell: the more active metal is the anode and will corrode, while the more noble metal acts as the cathode. The driving force for this corrosion is the potential difference between the two metals. Metals that are far apart on the galvanic series have a larger difference in electrochemical potential, which means a stronger driving force for electrons to flow and more rapid oxidation of the anode. Therefore, when the anode sits farther from the cathode on the series, the corrosion damage to the anode increases. In practice, factors like how large the anode area is relative to the cathode area, coatings, and the electrolyte also influence the rate, but the general principle holds: greater separation on the series leads to greater anodic damage.