Which metal is used for galvanizing iron?

The metal used for galvanizing iron is zinc. Galvanization is a process in which a thin protective layer of zinc is applied to the surface of iron or steel to prevent it from rusting. This method is widely used in industries because iron and steel, though strong, are easily damaged by moisture and oxygen, which cause corrosion.

Zinc is chosen for galvanization because it is more reactive than iron. When zinc is coated on iron, it acts as a sacrificial metal. This means that even if the zinc coating gets scratched and the iron is exposed, zinc will corrode first, protecting the underlying iron from rust. This protective action is due to zinc being more electropositive than iron in the electrochemical series.

There are different methods of galvanization, but the most common is hot-dip galvanizing. In this process, iron or steel is dipped into molten zinc, forming a strong protective coating. Another method is electro-galvanization, where zinc is applied using electric current.

Products that are often galvanized include water pipes, roofing sheets, car bodies, wire fences, and household tools. Galvanized iron is preferred because it lasts much longer in outdoor and moist conditions compared to untreated iron.

Other metals like aluminium, copper, or lead are not used for galvanizing iron because they do not provide the same sacrificial protection or are not cost-effective. Zinc, on the other hand, is abundant, affordable, and highly effective against rust.

In summary, galvanizing is a practical and economical method to protect iron and steel from corrosion, and the metal used for this process is zinc. This concept belongs to Chemistry, specifically the study of metals, corrosion, and protective coatings.