# Which process represents oxidation with respect to the metal centre? "A. "Fe(s)+2HCl(aq) rarr FeCl_2(aq) + H_2(g) "B. "FeCl_2(s)+H_2(aq) rarr Fe(s) + 2HCl(aq) "C. "Fe(NO_3)_2(aq)+2HCl(aq) rarr FeCl_2(aq) + 2HNO_3(aq) "D. "Fe_2O_3(s) + H_2(g)

Aug 31, 2016

$\text{Option A}$

#### Explanation:

Iron undergoes the redox process: $F {e}^{0} \rightarrow F {e}^{2 +}$.

The hydrogen ion is reduced to dihydrogen gas.

Oxidation:

$F e \rightarrow F {e}^{2 +} + 2 {e}^{-}$

Reduction:

${H}^{+} + {e}^{-} \rightarrow \frac{1}{2} {H}_{2} \uparrow$

Iron is oxidized.

#### Explanation:

One definition of oxidation and reduction is to look at the charge of the participants.

If the charge is reduced, that item was reduced.
If the charge is increased, that item was oxidized.

Iron went from the neutral state in Fe to the +2 state in the FeCl2. Its charge increased so it was oxidized.

Hydrogen went from the +1 state in the HCl to the neutral state in H2 so it was reduced.