Rusting process

Rusting process

Necessary conditions of Rusting Presence of oxygen (or air) Presence of water

Rusting process

Rusting process

Conditions that accelerate rusting Presence of a strong electrolyte (e.g. salt solution - a good conductor) Presence of a less reactive metal e.g Sn, Cu Presence of acid Bent or Sharp angled iron article The speed of rusting can be monitored by a yellow rust indicator which will turn blue in the presence of rust (Fe2+(aq) ion).

Presence of strong electrolyte (e.g. sea water) Strong electrolyte enhances the conductivity of the solution and speeds up the rusting process.

Presence of less reactive metal (e.g. Sn, Zn) A scratched tin-plated iron can rusts more quickly than an ordinary iron can.

Presence of less reactive metal (e.g. Sn, Cu)

 Why does a scratched tin-plated iron can rust more quickly than an ordinary iron can ? As tin is less reactive than iron, iron will lose electrons through tin at a faster speed than if tin is absent. Therefore, the can will rust more quickly.

Presence of acid In the presence of acid, Fe(s) forms Fe2+(aq) ions more readily and rusts faster. Fe(s) + 2H+(aq)  Fe2+(aq) + H2(g)

Conditions accelerate rusting Presence of a strong electrolyte (e.g. salt solution - a good conductor) Presence of a less reactive metal e.g Sn, Cu Presence of acid Bent or Sharp angled iron article The speed of rusting can be monitored by a yellow rust indicator which will turn blue in the presence of rust (Fe2+(aq) ion).