Corrosion is a redox reaction where metals become worn and disintegrated, resulting in the inability of further use. A redox reaction involves the transfer of electrons from one element to another, whereby the element which loses electrons is the reductant and the element which gains electrons is the oxidant.
The rusting of iron(hydrated iron(111) oxide) is an example of corrosion, which is under gone everyday. The rusting of iron is an electrochemical process,. This process involves a number of steps, starting with the oxidation of the Iron.
Fe(s) → Fe2+(aq) = 2e-
Oxygen is then dissolved in the water resulting in the element losing electrons to become the reductant.
O2(aq) + 2H2O(l) + 4e- → 4OH-(aq)
From these two reactions an iron(11) hydroxide solution is created and then precipitated.
Fe2+(aq) + 2OH-(aq) → Fe(OH)2(S)
This solution is then oxidised, hence forming the hydrated iron(3) oxide or rust.
4Fe(s) + 302(aq) + 2H20(l) → 2Fe2O3.H2O(s)
=Fe2O3.xH2O – X is commonly 1 or 2.
Electrolytes in sea water help by increasing conductivity of the water, providing a path between the anode and cathodes. When Iron is oxidised, areas of the Iron which are exposed to oxygen