Which of the following is NOT a non-ferrous metal?

The correct answer is Iron, as it is categorized as a ferrous metal. Ferrous metals contain iron, which gives them properties such as increased strength and durability, but also makes them susceptible to rusting in the presence of moisture. Non-ferrous metals, on the other hand, do not contain significant amounts of iron and are typically more resistant to corrosion.

Aluminium, copper, and brass are all classified as non-ferrous metals. Aluminium is prized for its lightweight and corrosion resistance, making it a popular choice in construction and manufacturing. Copper is known for its excellent conductivity of electricity and heat, which makes it important in electrical applications. Brass, an alloy of copper and zinc, is often used for decorative purposes and in plumbing applications due to its workability and resistance to corrosion. Understanding these classifications helps in selecting the right materials for specific applications in industrial maintenance.