Can sulfuric acid be made at home using sodium thiosulfate?
A few days ago, I extracted elemental iodine at home from tincture of iodine, HCL (31.45%, 10.3 M) and H202 (3%), then filtered and evaporated the crystals to dryness. After collecting and storing the crystals, I decided to store the dark red liquid left over (filtrate) to investigate the best way to neutralize and dispose of it. I discovered that the free iodine ions can be neutralized using sodium thiosulfate, which I had in my lab. After adding 5 g of sodium thiosulfate, the solution turned a cloudy yellow and a yellow precipitate formed on the bottom.
Researching around the web, I found that two reactions took place by the addition of the sodium thiosulfate:
1. sodium thiosulfate solution
and HCL:
HCl + Na2S2O3 → NaCl + SO2 + S + H2O
(I did notice a yellow colored precipitate settle on the bottom of the container. I think this is probably solid sulfur mixed with NaCl).
2. sodium thiosulfate and H202 yielding sulfuric acid as a product:
Na2S2O3 + 4H2O2 → Na2SO4 + H2SO4 + 3H2O
I decided to test the cloudy, pale yellow solution with universal pH indicator paper and it turned the strip a dark red, indicating highly acidic solution.
My question is: If H2SO4 is indeed producted, how difficult would it be to filter out the solid sulfur and NaCl at the bottom, and the sodium sulfate to get the H2SO4?
Filter, collect the filtrate H2SO4, wash, then purify possibly?
Would this be a practical way of making sulfuric acid (assuming the forumulas I wrote above are correct)? Perhaps not too efficient, but sodium thiosulfate and H202 are relatively cheap, so perhaps something can be said for this method. I'd like to hear your thoughts on this way of generating sulfuric acid.
