Aluminum reacts with aqueous copper (II) chloride to produce copper plus aluminum
chloride. a. Write a balanced equation for this reaction.

Al(s)  +  3CuCl₂(aq) → 3Cu(s)  +  2AlCl₃(aq)

Explanation:

We define the reactants:

Al(s) and CuCl₂ (aq)

Our products are: Cu(s) and AlCl₃

This is a redox reaction where the Al and the Cu, change the oxidation state

Al(s) → Al³⁺ + 3e⁻  ⇒ Oxidation

Cu²⁺(aq) + 2e⁻ → Cu(s)    ⇒ Reduction

We multiply both reactions, in order to have the electrons balanced

(Al(s) → Al³⁺ + 3e⁻  ) .2 ⇒ 2Al(s) → 2Al³⁺ + 6e⁻

(Cu²⁺(aq) + 2e⁻ → Cu(s) ) .3   ⇒ 3Cu²⁺(aq) + 6e⁻ → 3Cu(s)

We sum both half reactions, to cancel the electrons:

2Al(s) +  3Cu²⁺(aq) + 6e⁻  →  3Cu(s)  +  2Al³⁺ + 6e⁻

We add the chlorides, to get the balanced reaction

Balanced reaction is: Al(s)  +  3CuCl₂(aq) → 3Cu(s)  +  2AlCl₃(aq)