Chapter 3 Electrochemistry, Chemistry class 12 Chapter 3 Electrochemistry Chemistry, Class 12 | Page 28

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