What is corrosion? Explain the conditions necessary for the rusting of iron and suggest two methods to prevent it.

Corrosion is the gradual deterioration of a material, usually a metal, by chemical reaction with its environment. Rusting is a specific type of corrosion that affects iron and its alloys. The conditions necessary for rusting of iron are the presence of both oxygen (from air) and water (moisture). Two methods to prevent rusting include painting (which creates a barrier between the iron and the environment) and galvanization (coating iron with a layer of zinc, which acts as a sacrificial metal).