Question

Account for the following:

Iron on reaction with HCl forms FeCl₂ and not FeCl₃.

Answer 1

• Iron reacts with $\mathrm{HCl}$ to form ${\mathrm{FeCl}}_2$ and ${\mathrm{H}}_2$.
• $\mathrm{Iron}+\mathrm{Hydrochloric}\mathrm{acid}\to \mathrm{Iron}\mathrm{chloride}+\mathrm{Hydrogen}$
• i.e., $\mathrm{Fe}\left(\mathrm{s}\right)+2\mathrm{HCl}\left(\mathrm{aq}\right)\to {\mathrm{FeCl}}_2\left(\mathrm{aq}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)$
• The hydrogen gas which is produced in the reaction prevents the oxidation of ${\mathrm{FeCl}}_2$ to ${\mathrm{FeCl}}_3$.

Thus, Iron on reaction with HCl forms FeCl₂ and not FeCl₃.