Answer
$4Fe_{(s)}+3(O_{2})_{(g)}=2(Fe_{2}O_{3})_{(s)}$
Work Step by Step
When solid iron reacts with the oxygen present in air, it leads to the formation of iron (III) oxide, which is also called rust.
The balanced chemical equation for the reaction is,
$4Fe_{(s)}+3(O_{2})_{(g)}=2(Fe_{2}O_{3})_{(s)}$