When iron is exposed to moist air, it gradually rusts. This is due to the formation of

When iron is exposed to moist air, it gradually rusts due to the formation of hydrated iron (III) oxide. This happens when iron reacts with oxygen and water in the air, producing hydrated iron (III) oxide, which is a reddish-brown compound commonly known as rust. The reaction of iron with oxygen is called oxidation, and the presence of water is necessary for the reaction to occur. Rusting of iron is a common example of corrosion, which can weaken structures and cause them to fail over time. Therefore, it is important to take measures to prevent rusting, such as using protective coatings or keeping the iron dry.