Question

What is corrosion, explain with example?

Answer 1

1. The metals degrade on coming in contact with an open environment.
2. The degradation of metals is called corrosion.
3. When metal comes in contact with air and water it starts deforming from the outer surface and produces flaky substances.
4. The reddish-brown flaky substances are called rust and the phenomenon is called Rusting of Iron.
5. The chemical reaction of rusting of Iron is represented as:
   $4\mathrm{Fe}\left(\mathrm{s}\right)+3{\mathrm{O}}_2\left(\mathrm{g}\right)+2{\mathrm{xH}}_2\mathrm{O}\left(\mathrm{l}\right)\to 2\underset{\left(\mathrm{Rust}\right)}{{\mathrm{Fe}}_2{\mathrm{O}}_3.{\mathrm{xH}}_2\mathrm{O}\left(\mathrm{s}\right)}$
6. Examples: Corrosion of Copper, Silver gets Tarnished, etc.
7. The chemical reaction involves the tarnishing of Silver is represented as:
   $2\mathrm{Ag}\left(\mathrm{s}\right)+{\mathrm{H}}_2\mathrm{S}\left(\mathrm{g}\right)\to {\mathrm{Ag}}_2\mathrm{S}\left(\mathrm{s}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$
8. Silver reacts with Hydrogen sulphide to form Silver sulphide and Hydrogen.