- Corrosion of metal = metal loses its electrons to form positive ions.
Corrosion of ironFe → Fe2+ + 2e
Corrosion of MagnesiumMg → Mg2+ + 2e
- The higher the position of a metal in the electrochemical series, the more electropositive (reactive) the metal is. The metal has a greater tendency to give away electrons to form the metal ion, that is the metal is more easily corroded.
- For instance, the metal magnesium corrodes more easily than copper because magnesium is more electropositive than copper.
- Corrosion of metal is a redox reaction as the metal loses electrons to oxygen and water, which act as the oxidising agents to receive the electrons.
- Corrosion of iron is also called rusting.Fe (s) → Fe2+ (aq) + 2e
- Rusting of iron can only occur if both oxygen and water are present.