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

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


2 Answers

Vasantha Kumari
askIITians Faculty 38 Points
8 years ago

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.

37 Points
8 years ago
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.

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