Corrosion is the process of slowly eating away of the metal due to attack of the atmospheric gases on the surface of the metal resulting into the formation of compounds such as oxides, sulphides, carbonates, etc. The corrosion of iron is called rusting.
The phenomenon of corrosion involves the destruction of metal in which metal is generally converted into oxide. Common examples are rusting of rion, tarnishing of silver and deposition of green coating on copper and bronze.
Factors affecting corrosion:
(a) Presence of oxygen, sulphur etc. (elements which gain electrons).
(b) Presence of moisture.
(c) Presence of carbon dioxide.
= 1.05 V – 0.0295 x log 80
= 1.05 V – 0.0295 x 1.9031
= 1.05 V – 0.056 = 0.99 V.