Iron is one of the earliest metals used by man. It is a relatively cheap and strong metal but its disadvantage is that its rust. When iron or an object made of iron is exposed to moist air, they can react chemically with oxygen in the air and OR with water to form HYDRATED IRON(ii)OXIDE which is called rust. It is a brown red powder.

3Fe(s) + 2O2 (g)                                 Fe3O4(aq)

Fe2O3 + XH2O                        Fe2O3.XH2O

Rust is not a pure substance because the water molecules (X) are not constant.

Conditions for rusting

• The presence of oxygen
• The presence of water

Methods of preventing rust

• by oiling or greasing
• by painting
•  by coating
• By galvanizing
• By alloying ( iron mixed with other metals such as; Aromium, Nickel, Stainless steel )