NCEES Fundamentals of Engineering (FE) Mechanical Practice Exam 2025 - Free FE Mechanical Practice Questions and Study Guide

The correct answer highlights a common yet effective method of protecting iron from corrosion. Iron is highly susceptible to oxidation, which is a primary cause of corrosion in ferrous materials. To inhibit this process, protective coatings are often applied.

Zinc is widely recognized for its galvanic properties when used as a coating on iron or steel. It serves as a sacrificial anode, meaning that zinc will corrode preferentially to iron, thereby protecting the underlying metal. This method, known as galvanization, vastly extends the life of iron components.

Gold, while an excellent conductor and resistant to corrosion itself, is not a practical or economical solution for protecting iron from corrosion. Similarly, while aluminum can also provide a degree of corrosion resistance through the formation of an oxide layer, it does not possess the same sacrificial properties specific to galvanization, making it less effective than zinc in this specific application.

In summary, the effectiveness of zinc in a galvanic system is why it is the preferred option for protecting iron from corrosion, as it actively prevents the oxidation process by corroding in place of the iron.