Which material is often used for sacrificial anodes in cathodic protection systems?

Zinc is commonly used for sacrificial anodes in cathodic protection systems due to its favorable electrochemical properties. Zinc has a more negative electrochemical potential compared to the structures it is protecting, such as steel and other metals, which allows it to corrode preferentially. By sacrificing itself, zinc protects the underlying metal from corrosion, effectively extending the lifespan of pipelines, ships, tanks, and other structures exposed to corrosive environments.

The high effectiveness of zinc as a sacrificial anode is further supported by its relative abundance and cost-effectiveness, making it a practical choice for many cathodic protection applications. Additionally, zinc anodes can perform well in a variety of environments, including both freshwater and seawater, which adds to their versatility in protective applications.

The materials mentioned in the other choices do not serve the same purpose as effectively as zinc in this context, with copper typically being used in cathodic protection systems as an impressed current anode rather than a sacrificial one, and lead and iron not having the ideal electrochemical properties to function efficiently as sacrificial anodes.