Question

How will you show that air and moisture both are required for rusting of iron?

Answer 1

oxygen is a very good oxidising agent,

so, $Fe\to F{e}^{2+}$ + $2e^{-}$

$O_2+H_{2}O+4H^{+}\to 4(OH{)}^{-}$

$F{e}^{2+}+2(OH{)}^{-}\to Fe(OH{)}_2$

$F{e}^{2+}+2H_{2}O\to Fe(OH{)}_2+2H^{+}$

hence, we can say that air and moisture both are required for rusting of iron.