Question

Which is the balanced half-reaction equation for the reduction of Al3+ to Al?

1. A13+ + 3e - Al
2. A13+ - Al + 3e
3. Al + 3e - A13+
4. Al - A13+ + 3e​

Answer 1

1. Al³⁺ + 3e⁻ → Al

Step-by-step explanation:

In a reduction, the oxidation number of a species is converted to a lower value.

In the following half-reaction:

• Al³⁺ + 3e⁻ → Al

The number of atoms is the same on both sides of the equation (one Al atom). The electrical charge is also the same, as there is a total charge of 0 on both sides.