Fig. Iron chain left in moist air got rusted
Corrosion causes damage to car bodies, bridges, iron railings, ships and to all objects made of metals, especially those of iron.
o In case of rusting of copper, the metallic copper reacts with oxygen, carbon-dioxide and atmospheric moisture and develops a green coloured coating of copper hydroxide and copper carbonate.
Fig. Copper developing green coloured rust on exposure to moist air o
In case of tarnishing of silver articles, the metallic silver reacts with hydrogen sulphide or sulphur present in air and gets tarnished.
Fig. Tarnished silver Vs polished silver