Complete and balance the following half-reaction in acidic solution. H2SO3(aq) -> SO4 2- (aq)

Answer 1

H₂SO₃(aq) ==> SO₄^2-(aq) .. unbalanced

H₂SO₃(aq) + H₂O(l) ==> SO₄^2-(aq) .. balanced for S and O

H₂SO₃(aq) + H₂O(l) ==> SO₄^2-(aq) + 4H⁺(aq) .. balanced for S, O and H using acid (H⁺)

H₂SO₃(aq) + H₂O(l) ==> SO₄^2-(aq) + 4H⁺(aq) + 2e- .. balanced for S, O, H and charge (balanced redox)

Answer 2

To balance the half-reaction for the conversion of sulfurous acid (H₂SO₃) to sulfate ion (SO₄ ^2-) in acidic solution, we need to follow these steps:

1. Write the unbalanced half-reaction.

2. Balance the elements other than hydrogen and oxygen.

3. Balance the oxygen atoms by adding water molecules (H₂O).

4. Balance the hydrogen atoms by adding H⁺ ions.

5. Balance the charge by adding electrons (e⁻).

The unbalanced half-reaction is:

H₂SO₃(aq) -----> SO₄ ^2-(aq)

Now, let's balance it step by step:

1. Balance the sulfur atoms:

H₂SO₃(aq) -----> SO₄ ^2-(aq)

2. Balance the oxygen atoms:

H₂SO₃(aq) -----> SO₄ ^2-(aq) + H₂O(l)

3. Balance the hydrogen atoms:

H₂SO₃(aq) + 2H⁺(aq) ----> SO₄ ^2-(aq) + H₂O(l)

4. Balance the charge:

H₂SO₃(aq) + 2H⁺(aq) + 2e^- -----> SO₄ ^2-(aq) + H₂O(l)

Now the half-reaction is balanced. It requires 2 electrons (2e^-)to balance the charge on both sides.