Question

Incorrect statement regarding rusting is

• A. metallic iron is oxidised to $ Fe^{3+} $ ions
• B. metallic iron is reduced to $ Fe^{2-} $ ions
• C. oxygen gas is reduced to oxide ion
• D. yellowish-brown product is formed

Answer 1

Answer: (B)

In the presence of $O_{2}$ and $H_{2} O$ rusting of iron takes place.
$H^{+}$ions act as a catalyst. It is believed that oxidation of $F e$ into $F e^{2+}$ occurs at a place which act as anode,
$F e \rightarrow F e^{2+}+2 e^{-}$(oxidation) (at anode) In the presence of $H^{+}$ions $O_{2}$ is reduced into $H_{2} O$ at a place which acts as cathode
$O _{2}+4 H ^{+}+4 e^{-} \rightarrow 2 H _{2} O$ (reduction) $Fe ^{2+}$ formed at anode are oxidised into $Fe ^{3+}$ by air.
$4 Fe ^{2+}+ O _{2}+4 H _{2} O \rightarrow 2 Fe _{2} O _{3}+8 H ^{+}$