Question

Which series of reactions correctly represent chemical relations related to iron and its compound?

Options

• \[\ce{Fe ->[Dil. H2SO4] FeSO4 ->[H2SO4, O2] Fe2(SO4)3 ->[Heat] Fe}\]

• \[\ce{Fe ->[O2, heat] FeO ->[dil. H2SO4] FeSO4 ->[Heat] Fe}\]

• \[\ce{Fe ->[Cl2, heat] FeCl3 ->[Heat, air] FeCl2 ->[Zn] Fe}\]

• \[\ce{Fe ->[O2, heat] Fe3O4 ->[CO, 600^\circ] FeO ->[CO, 700^\circ] Fe}\]

Answer 1

\[\ce{\mathbf{Fe \overset{O_2, heat}\leftarrow Fe_3O_4 \overset{CO, 600^\circ}\leftarrow FeO \overset{CO, 700^\circ} \leftarrow Fe}}\]

Explanation:

Iron reacts with oxygen on heating to form magnetite (Fe₃O₄).
This oxide of iron is then reduced step by step by carbon monoxide (CO) at high temperatures:

Iron to iron oxide:

\[\ce{Fe + O2 -> Fe3O4}\]

Iron oxide to Ferrous oxide (at about 600° C):

\[\ce{Fe3O4 + CO -> FeO}\]

Ferrous oxide to iron (at about 700° C):

\[\ce{FeO + CO -> Fe}\]

This sequence correctly represents the chemical reactions of iron and its compounds, especially the reduction of iron oxides during the extraction of iron.