The Effects of Oxidation ReactionsCorrosion:-Many metals are chemically active elements and get easily affected by substances like moisture, air, acids, etc. One must have observed iron articles that are shiny when new, but get coated with a reddish brown powder when left for some time. This process is commonly known as rusting of iron. The problem with iron (as well as many other metals) is that oxidation takes place and the oxide formed does not firmly adhere to the surface of the metal causing it to flake off easily. This eventually causes structural weakness and disintegration of the metal.When a metal is attacked by substances around it, it is said to corrode and this process is called corrosion. Corrosion causes deterioration of essential properties in a material.What happens to copper vessels or artifacts when exposed to air and water? They slowly get tarnished by acquiring a thin green oxide layer. Similarly, silver quickly acquires a thin black oxide coating in moist air. The heaviest metal lead also tarnishes in moist weather. The black coating on silver and the green coating on copper are examples of corrosion in which the oxides formed strongly bond to the surface of the metal, preventing the surface from further exposure to oxygen and consequently slowing down corrosion.Billions of rupees are lost each year because of corrosion and a huge amount of money is spent in prevention of corrosion and tarnishing of metals. Corrosion causes damage to car bodies, buildings, bridges, iron railings, underground water and sewage pipes, ships and all objects made of metals. Much of this loss is due to the corrosion of iron and steel, although many other metals may corrode as well. You will learn more about corrosion in Chapter 3.