[bugsmenot]

I need help balancing this redox reaction. The question is asking me to balance a bunch of reactions and the last one is stumping me. It is also asking to balance them using the half-reaction method and oxidation number method, btw.

S₂O₄^2- + O₂ -> SO₄^2- (BASIC)

I've managed to balance it with the oxidation number method.

6e /S₂O₄^2- X 2
4e/O₂ X 3

4 OH + 2 H2O + 2S₂O₄^2- + 3O₂ -> 4SO₄^2- + 4H + 4OH
4 OH + 2S₂O₄^2- + 3O₂ -> 4SO₄^2- + 2H2O

I hope that that is correct. Now the problem is the half-reaction method. No matter what I do I just can't seem to balance the reaction. I've done it quite a few times, and I still can't get it. I think the problem is that the elements being oxidized and reduced are in the same compound. I'm really stumped. Help, please.

[Borek]

Show your half reactions.

[bugsmenot]

4 [8OH + S₂O₄ + 4H₂O-> 2SO₄ +6e + 8H₂O]
3 [2O₂ + 8e-> SO₄]

[Alberto_Kravina]

3 [2O₂ + 8e-> SO₄]

4 [8OH + S2O4 + 4H2O-> 2SO4 +6e + 8H2O]

This one seems to be OK.

[Borek]

4 [8OH + S2O4 + 4H2O-> 2SO4 +6e + 8H2O]

This one seems to be OK.

Water?

Second one is a disaster. Try O₂ -> OH^-.