Question

When the following oxidation-reduction occurs, what is the balanced reduction half-reaction after the electrons in both half reactions are balanced? Al (s) + Cu2+ (aq) → Al3+ (aq) + Cu (s) View Available Hint(s) When the following oxidation-reduction occurs, what is the balanced reduction half-reaction after the electrons in both half reactions are balanced? Al (s) + Cu2+ (aq) → Al3+ (aq) + Cu (s) 2Al (s) → 2Al3+ (aq) + 6e− Al (s) → Al3+ (aq) + 3e– Cu2+ (aq) + 2e− → Cu (s) 3Cu2+ (aq) + 6e− → 3Cu (s)

Answer 1

Answer :  The balanced reduction half-reaction is:

$3Cu^{2+}+6e^-\rightarrow 3Cu$

Explanation :

Redox reaction or Oxidation-reduction reaction : It is defined as the reaction in which the oxidation and reduction reaction takes place simultaneously.

Oxidation reaction : It is defined as the reaction in which a substance looses its electrons. In this, oxidation state of an element increases. Or we can say that in oxidation, the loss of electrons takes place.

Reduction reaction : It is defined as the reaction in which a substance gains electrons. In this, oxidation state of an element decreases. Or we can say that in reduction, the gain of electrons takes place.

The given balanced redox reaction is :

$Al(s)+Cu^{2+}(aq)\rightarrow Al^{3+}(aq)+Cu(s)$

The half oxidation-reduction reactions are:

Oxidation reaction : $Al\rightarrow Al^{3+}+3e^-$

Reduction reaction : $Cu^{2+}+2e^-\rightarrow Cu$

In order to balance the electrons, we multiply the oxidation reaction by 2 and reduction reaction by 3 and then added both equation, we get the balanced redox reaction.

Oxidation reaction : $2Al\rightarrow 2Al^{3+}+6e^-$

Reduction reaction : $3Cu^{2+}+6e^-\rightarrow 3Cu$

The balanced redox reaction will be:

$2Al(s)+3Cu^{2+}(aq)\rightarrow 2Al^{3+}(aq)+3Cu(s)$

Thus, the balanced reduction half-reaction is:

$3Cu^{2+}+6e^-\rightarrow 3Cu$