What is a disadvantage of sacrificial anodes?

The correct answer highlights a key limitation of sacrificial anodes, which is their small area of coverage per anode. Sacrificial anodes are used to protect metal structures from corrosion by providing a more electrochemically active metal that corrodes instead of the structure itself. However, each anode typically only protects a limited area, which means that multiple anodes might be necessary to adequately cover a larger structure. This requirement can lead to increased material and installation costs, as well as complicate maintenance and monitoring efforts.

Other factors such as maintenance levels, environmental conditions, and effectiveness under specific circumstances may influence the usage of sacrificial anodes, but the fundamental limitation of their coverage area directly relates to their effectiveness and efficiency in preventing corrosion over broader surfaces.