Question

Onsider a galvanic cell in which al3 is reduced to elemental aluminum, and magnesium metal is oxidized to mg2 . write the balanced half-cell reactions that take place at the cathode and at the anode.

Answer 1

In a galvanic cell, the reduction half-reaction occurs at the cathode, while the oxidation half-reaction occurs at the anode. The balanced half-reactions for this cell are Al3+ + 3e- → Al (cathode) and Mg → Mg2+ + 2e- (anode).

Step-by-step explanation:

In a galvanic cell, the reduction half-reaction occurs at the cathode, while the oxidation half-reaction occurs at the anode. In this case, aluminum (Al) is reduced to elemental aluminum (Al) and magnesium (Mg) is oxidized to Mg2+.

The balanced half-reactions are:

Cathode: Al3+ + 3e- → Al

Anode: Mg → Mg2+ + 2e-

Answer 2

Two Half Cell reactions are as follow,

3e⁻ + Al⁺³ → Al (Reduction Reaction)

Mg → Mg⁺² + 2e⁻ (Oxidation Reaction)

In order to balance the number of electrons, multiply reduction reaction by 2 and oxidation reaction by 3.
So,
6e⁻ + 2 Al⁺³ → 2 Al

3 Mg → 3 Mg⁺² + 6e⁻ (e⁻ cancelled)
_______________________

2 Al⁺³ + 3 Mg → 2 Al + 3 Mg⁺²

Result:
At Anode Magnesium metal is Oxidized and At Cathode Aluminium Ions are reduced.