What is the primary mechanism of an oxygen concentration cell?

The primary mechanism of an oxygen concentration cell involves corrosion due to reduced oxygen content. In this type of cell, an electrochemical reaction occurs where areas with lower oxygen concentration become anodic (corroding) compared to areas with higher oxygen concentration, which act as cathodic regions. This difference in oxygen concentration creates a potential difference, leading to localized corrosion effects.

In practical terms, when certain areas of a metal surface are shielded from oxygen—such as by marine growth, paint, or deposits—these areas can suffer from corrosion because the conditions are favorable for the anodic reaction. As a result, water and metal can interact without sufficient oxygen to protect the metal surface, leading to accelerated degradation.

The other options do not accurately describe the mechanism of an oxygen concentration cell. Uniform corrosion refers to a more even and widespread form of corrosion, rather than localized differences in oxygen content. Localized corrosion due to electric shocks doesn't pertain specifically to oxygen concentration cells, and corrosion through chemical exposure involves chemical reactions rather than the electrochemical processes driven by oxygen levels in the environment. Therefore, identifying reduced oxygen content as the primary mechanism captures the essence of how oxygen concentration cells operate.