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# Rusting Rusting is a chemical reaction that is not useful. To prevent rusting, we need to prevent the direct contact of iron with oxygen and water. This can be done by coating iron with a protective layer or using alloys. Some ways to prevent rusting are shown in Figure 7.31. * Some iron lamp...

# Rusting Rusting is a chemical reaction that is not useful. To prevent rusting, we need to prevent the direct contact of iron with oxygen and water. This can be done by coating iron with a protective layer or using alloys. Some ways to prevent rusting are shown in Figure 7.31. * Some iron lamp posts are coated with a layer of zinc to form a protective layer to prevent rusting. * Railings can be made of the alloy stainless steel. Stainless steel is formed when iron is mixed with chromium and other substances. Stainless steel is much less likely to rust than iron. * Iron fences are coated with paint to form a protective layer to prevent rusting. **Figure 7.31** (Image description: A diagram depicting a building with different features that illustrate methods of preventing rusting. A street lamp post is coated with zinc for protection. Iron fences are depicted with paint to prevent rust. Different materials are labeled to illustrate the various methods) **Think About It** If your bicycle is starting to rust, what can you do to prevent it from rusting further? **Key Points** * Some chemical reactions are useful, such as those involved in photosynthesis, digestion and aerobic respiration. * Some chemical reactions are not useful, such as the corrosive action of acids on marble and limestone, the reaction of chlorofluorocarbons with ozone and rusting.