Here's how to balance the half-reaction for the conversion of sulfate ion (SO₄²⁻) to sulfite ion (SO₃²⁻):

1. Identify the Reactants and Products:

* Reactant: Sulfate ion (SO₄²⁻)

* Product: Sulfite ion (SO₃²⁻)

2. Balance the Oxygen Atoms:

* Add one water molecule (H₂O) to the product side to balance the oxygen atoms:

SO₄²⁻ → SO₃²⁻ + H₂O

3. Balance the Hydrogen Atoms:

* Add two hydrogen ions (H⁺) to the reactant side:

SO₄²⁻ + 2H⁺ → SO₃²⁻ + H₂O

4. Balance the Charges:

* The charges on both sides are now balanced:

SO₄²⁻ + 2H⁺ + 2e⁻ → SO₃²⁻ + H₂O

The balanced half-reaction is:

SO₄²⁻ + 2H⁺ + 2e⁻ → SO₃²⁻ + H₂O