Question

Give one word for the following statement.

The brown flaky coating formed on iron when exposed to moist air.

Answer 1

Formation of brown flaky coating on iron:

• When iron is exposed to moist air it reacts with the oxygen present in the air to form ferrous oxide.
• This is a brown flaky layer coating formed on iron and causes the destruction of iron.
• This formation is known as rust, and the process is known as rusting.

$\underset{\mathrm{Iron}}{4\mathrm{Fe}\left(\mathrm{s}\right)}+\underset{\mathrm{Oxygen}}{2{\mathrm{O}}_2\left(\mathrm{g}\right)}\stackrel{\mathrm{Moisture}}{\to }\underset{\mathrm{Ferrous}\mathrm{oxide}}{2{\mathrm{Fe}}_2{\mathrm{O}}_3\left(\mathrm{s}\right)}$

Hence, the answer is rust.