Question

What do you mean by rusting? Describe it with a proper chemical equation.

Answer 1

Part I - Rusting

When iron is left exposed to air it leads to the formation of a reddish-brown powdered mass on the upper layer of iron which is formed due to oxidation of iron when iron comes in contact with air + water. Hence this brown powdered mass formed on the upper layer of iron is known as rust and the process of rust formation is known as rusting.

Part II - Chemical Equation for rusting

For Rusting it is necessary that iron should come in contact with oxygen and water.

$\underset{\mathrm{Iron}}{4\mathrm{Fe}\left(\mathrm{s}\right)}+\underset{\mathrm{Oxygen}}{3{\mathrm{O}}_2\left(\mathrm{g}\right)}+\underset{\mathrm{Water}}{{\mathrm{xH}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\left(\mathrm{Rust}\right)}{\underset{\mathrm{Iron}\left(\mathrm{III}\right)\mathrm{Oxide}}{2{\mathrm{Fe}}_2{\mathrm{O}}_3.{\mathrm{xH}}_2\mathrm{O}\left(\mathrm{l}\right)}}$