Chemistry Forum

How do I write this as a balanced chemical equation? I am trying to write the chemical equation reduction of the substituted phenylarsonic acid with dithionite which produces Salvarsan. Check the attachment below to help you out.

I got this far but I don't even think this is even close to being right:
C₆AsNH₆O₆+Na₂S₂O₄+H₂O—--->C₁₂H₁₂As₂N₂O₂+Na₂SO₃+Na₂SO₄+H₂O

Thank you!

Dithionite to sulfate

S₂O₄ 2- + 4 H₂O => 2 SO₄ 2- + 8 H+ + 6 e-

Arsenic acid to Salvarsan

2 RAsO₃H₂ + 8 H+ + 8 e- => RAs=AsR + 6 H₂O

Nitrogroup 2 RNO₂ + 12 H+ + 12 e- => 2 RNH₂ + 4 H₂O

Sum Reduction
2 RNO₂AsO₃H₂ + 20 H+ + 20 e - => NH₂RAs=AsRNH₂ + 10 H₂O

KgV of electrons = 60

10 S₂O₄ 2- + 40 H₂O => 20 SO₄ 2- + 80 H+ + 60 e-

6 RNO₂AsO₃H₂ + 60 H+ + 60 e - => 3 NH₂RAs=AsRNH₂ + 30 H₂O

Addition

6 RNO₂AsO₃H₂ + 10 S₂O₄ 2- + 10 H₂O => 3 NH₂RAs=AsRNH₂ + 20 H+ + 20 SO₄₂-

Add sodium

6 RNO₂AsO₃H₂ + 10Na₂S₂O₄ + 10 H₂O => 3 NH₂RAs=AsRNH₂ + 20 NaHSO₄

Thank you so much that was really helpful! I really appreciate it you are a life saver.

I was just wondering what does KgV of electrons mean?

It is like in Mathematics. 1/2 +1/3 = ?
The kgV ( kleinste gemeinsame Vielfache = least common multiple) is 6 so convert to 3/6 + 2/6 = 5/6
The same you do with the electrons in oxidation and reduction equation.