Question

Balance the following net ionic equationAl(s) + Cu2+(aq) n Al3+(aq) + Cu(s)

Answer 1

Given:

`Al_((s))+\text{ Cu}_((aq))^(2+)\rightarrow Al_((aq))^(3+)+\text{ Cu}_((s))`

Required: To balance the equation.

Solution

Step 1: Write the half reactions.

The aluminum is oxidized since the oxidation state increases from zero to plus three. The copper is reduced since the oxidation state decreases from 2+ to zero. The half reactions are as follows.

`\begin{gathered} Cu_((aq))^(2+)\text{ + 2e}^-\rightarrow Cu_((s))\text{ \lparen reduction\rparen} \\ \\ Al_((s))\rightarrow Al_((aq))^(3+)+\text{ 3e}^-\text{ \lparen oxidation\rparen} \end{gathered}`

Step 2: Multiply by an appropriate factor to balance the equation

Multiply the reduction reaction by 3

Multiply oxidation reaction by 2

Add the half reactions to get the net ionic equation:

Answer

`3Cu_((aq))^(2+)\text{ + 2Al}_((s))\rightarrow3Cu_((s))\text{ + 2Al}_((aq))^(3+)`