explain how rusting of iron is envisaged as setting of an electrochemical series

The term corrosion refers to degradation of metals in their chemical interaction with the environment and usually we refer to steel in this process. Metals that are in a metastable state will lose energy as they have little mechanical strength. These corrosion reactions are electrochemical in nature and a mixed anodic and cathodic reaction happens at its surface. This mixed electrode is a complete electrochemical cell on a single metal.

Metals of differing electrochemical properties come in contact a galvanic couple is formed.
We can predict these galvanic effects by studying the galvanic series comprising metals and alloys in order of their potentials in the corrosive environment.

Thanks & Regards,

Vasantha Sivaraj,

askIITians faculty.

Rusting of iron form an electrochemical cell.The reaction is take place in presence of water. An electrochemical cell is created on an iron object that has a distinct anode and cathode. * At one spot iron loses electrons (is oxidized) to form iron (II) ions. Fe (s)?Fe2+ (aq) + 2e- (the anodic site of our electrochemical cell) * At another spot oxygen in the air combines with water and forms hydroxide ions. ½O2 (g) + H2O (l) + 2e-? 2OH- (aq)(the cathodic site of our electrochemical cell) * In the presence of oxygen iron further oxidizes at the anode (loses electrons) to become iron (III) ions. Fe 2+ (aq)? Fe3+ (aq) + e- * The iron (III) ions and the hydroxide combine to form rust. 2Fe 3+ (aq) + 6OH- (aq)? Fe2O3 (s) + 3 H2O (l) Hence, rusting of iron act as electrochemical cell.