Electrochemical Theory of Rusting
Corrosion Of Iron Corrosion is the process in which a metal is destructed as a result of its reaction with environment. Corrosion of iron is known as rusting. Rusting is the hydrated ferric oxide. Other examples for corrosion are tarnishing of silver and development of green coating on copper and bronze. In corrosion metals undergo anodic oxidation to metal oxides. Electrochemical theory of rusting The rusting of iron is an electrochemical process involving the following steps. The moister containing CO2 acts as electrolyte. H 2 O + CO 2 ------> H 2 CO 3 H 2 CO 3 ------> 2H+ + CO 3 2- The iron is oxidized by the removal of electrons and acts as the anode. Fe ------> Fe 2+ + 2electron The H+ ions from the electrolyte accept electrons from the adjacent areas on metal surface and function as cathode. 4H + + 4electron ------> 2H 2 The atmospheric oxygen moves hydrogen as water. 2H 2 + O 2 ------> 2H 2 O Adding the above two equations, 4H+ +O 2 + 4electron ------> ...