Question

Which of the following oxide(s) of iron would be obtained on the prolonged reaction of iron with steam?

• A. $\mathrm{FeO}$
• B. ${\mathrm{Fe}}_2{\mathrm{O}}_3$
• C. ${\mathrm{Fe}}_3{\mathrm{O}}_4$
• D. ${\mathrm{Fe}}_2{\mathrm{O}}_3$ and ${\mathrm{Fe}}_3{\mathrm{O}}_4$

Answer 1

The correct option is C

${\mathrm{Fe}}_3{\mathrm{O}}_4$

The explanation for the correct answer

(C) ${\mathbf{Fe}}_{\mathbf{3}}{\mathbf{O}}_{\mathbf{4}}$

• Iron$\left(\mathrm{Fe}\right)$ on prolonged reaction with steam produces Iron($\mathrm{II},\mathrm{III}$)oxide$\left({\mathrm{Fe}}_3{\mathrm{O}}_4\right)$ and Hydrogen gas$\left({\mathrm{H}}_2\right)$.
• The reaction can be written as
• $$\begin{gathered} 3\mathrm{Fe}\left(s\right)+4{\mathrm{H}}_2\mathrm{O}\left(g\right)\to {\mathrm{Fe}}_3{\mathrm{O}}_4\left(s\right)+{\mathrm{H}}_2\left(g\right) \\ \left(\mathrm{Iron}\right)\left(\mathrm{Steam}\right)(\mathrm{Iron}(\mathrm{II},\mathrm{III})\mathrm{Oxide})\left(\mathrm{Hydrogen}\right) \end{gathered}$$
• $\mathrm{Fe}$ in ${\mathrm{Fe}}_3{\mathrm{O}}_4$exists in$+2,+3$ oxidation state.

Hence, Option (C) ${\mathbf{Fe}}_{\mathbf{3}}{\mathbf{O}}_{\mathbf{4}}$ is correct.

The Explanation for Incorrect answer

(A) $\mathbf{FeO}$

• Iron on prolonged reaction with steam produces${\mathrm{Fe}}_3{\mathrm{O}}_4$.
• So $\mathrm{FeO}$ is a wrong answer

(B) ${\mathbf{Fe}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{3}}$

• Iron on prolonged reaction with steam produces${\mathrm{Fe}}_3{\mathrm{O}}_4$.
• So ${\mathrm{Fe}}_2{\mathrm{O}}_3$is a wrong answer.

(D) ${\mathbf{Fe}}_{\mathbf{2}}{\mathbf{O}}_{\mathbf{3}}$ and ${\mathbf{Fe}}_{\mathbf{3}}{\mathbf{O}}_{\mathbf{4}}$

• Iron on prolonged reaction with steam produces only${\mathrm{Fe}}_3{\mathrm{O}}_4$.
• So ${\mathrm{Fe}}_2{\mathrm{O}}_3$and${\mathrm{Fe}}_3{\mathrm{O}}_4$ is a wrong answer.

Therefore, Option (C) ${\mathbf{Fe}}_{\mathbf{3}}{\mathbf{O}}_{\mathbf{4}}$ is correct.