First, let's balance the non-hydrogen and non-oxygen elements:
H₂SO₃(aq) → SO₂²-(aq) + 2H+(aq)
Next, let's balance the oxygen atoms by adding water (H₂O) molecules:
H₂SO₃(aq) + H₂O(l) → SO₂²-(aq) + 2H+(aq)
Now, let's balance the hydrogen atoms by adding hydrogen ions (H⁺):
H₂SO₃(aq) + H₂O(l) → SO₂²-(aq) + 2H⁺(aq) + 2e⁻
The final balanced half-reaction in acidic solution is:
H₂SO₃(aq) + H₂O(l) → SO₂²-(aq) + 2H⁺(aq) + 2e⁻
i think