What is corrosion? State condiyions necessary for rusting of iron. How is rusting harmful?
Corrosion. The process of eating away of the metal surface by the action of atmospheric reagents like water, oxygen and acids changing the metal into its compound is called corrosion. Rusting of iron. When iron objects are exposed to atmosphere, they are attacked by air and moisture (water) of the atmosphere and a brown and orange coloured layer is formed on the surface. It is called rust which is mainly hydrated iron (III) oxide Fe2O3. xH2O. Harmful effect of rusting. Hydrated iron (III) oxide is a brittle substance and falls off from the surface of iron and thus the object is damaged. Holes, cavities and roughness of surfaces are the result of rusting of an iron object. Conditions necessary for rusting: Open surface of the metal Presence of air (oxygen) Presence of moisture (water).
