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`