Which chemical reaction is responsible for rust on iron and steel?

Oxidation

Rust is the result of an oxidation chemical reaction where iron reacts with oxygen in the presence of water or moisture, forming iron oxide, commonly known as rust. This reaction not only degrades the appearance of iron objects but can also compromise their structural integrity. To combat this process, various protection methods are employed, such as painting or galvanizing. Understanding the chemistry of rust is crucial in many fields, from the conservation of historical monuments to the durability of modern infrastructures.