Question

Explain the factors which promote corrosion.

Answer 1

Corrosion is a natural process that occurs when pure metals react with things such as water or air, causing them to change into undesirable chemicals. This reaction produces metal degradation and disintegration, commencing with the exposed region of the metal and progressing to the total mass of the metal.

The two circumstances that leads to corrosion are as follows:

1. Corrosion occurs when there is an abundance of oxygen $\left({\mathrm{O}}_2\right)$.
2. Corrosion is also caused by the presence of contaminants such as Carbon dioxide $\left({\mathrm{CO}}_2\right)$ and Chloride $\left({\mathrm{Cl}}^{-}\right)$.

Chemical equation of corrosion can be shown as follows:

$\underset{\mathrm{Iron}}{4\mathrm{Fe}\left(\mathrm{s}\right)}+\underset{\mathrm{Oxygen}}{3{\mathrm{O}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Water}}{6{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\mathrm{Iron}\mathrm{hydoxide}}{4\mathrm{Fe}{\left(\mathrm{OH}\right)}_3\left(\mathrm{s}\right)}$