A voltaic cell is constructed with a Cu/Cu2 half-cell and an Ni/Ni2 half-cell. The nickel electrode is negative. Write both balanced half-reactions and the overall reaction. Recall that states of matter are not included for electrons transferred in the reaction but be sure to include states of matter for the other materials in your reaction statement.

Ni (s) → Ni²⁺ (aq) 2 e⁻

Cu²⁺ (aq) + 2 e⁻ → Cu (s)

Ni (s) + Cu²⁺ (aq) → Ni²⁺ (aq) + Cu (s)

Explanation:

A voltaic cell is constructed with a Cu/Cu²⁺ half-cell and an Ni/Ni²⁺ half-cell. The nickel electrode is negative (anode) and the copper electrode is positive (cathode). In the anode takes place the oxidation and in the cathode takes place the reduction. The corresponding half-reactions are:

Anode (oxidation) : Ni (s) → Ni²⁺ (aq) 2 e⁻

Cathode (reduction) : Cu²⁺ (aq) + 2 e⁻ → Cu (s)

The overall reaction is:

Ni (s) + Cu²⁺ (aq) → Ni²⁺ (aq) + Cu (s)