electrolysis of 30% H2SO4

[acx01b]

Hi,

electrolysis with platine of H2SO4(30%) 12V 0.7A
let's do this for 48hours with 50mL of 30% H2SO4 (d=1.26, 18,9g(0.2mol) of H2SO4 and 44.1g (3mol H2O)
to simplify let's say that all the H2O will disapear first, then the H2S2O8, and no H2SO5 will be formed
H2O --> H2 + 1/2 O2 at 0.25mol/h 24hours are needed
then 2 H2SO4 --> H2S2O8 + H2 at 0.25mol/h 2hours are needed...
i guees if some H2O2 is formed (H2S2O8 + 2H2O --> 2 H2SO4 + H2O2) it will disapear (H2O2 --> H2 + O2)
and after 30 hours we would get pure H2SO4 by adding good amount of H2O and NaCl...

i try now i'll tell you the results (how many ml obtained, intensity compared to time and problems or not to keep the solution cold, mixing every hour)

[acx01b]

ok after 40hours 80% sulfuric acid has been obtained : )

joke I bought some 80% H2SO4 today at the drugstore:
(by the way in every countries in brico stores you can find 75-80% H2SO4 for drain treatment)
so let's try with 20mL of this acid: (density 1.7, 0.28mol of H2SO4, 0.38mol of H2O)
H⁺ + 1e^- --> H₂
so 0.75mol of e^- is needed to convert all the H2O to gaz,
and 2 HSO4^- --> H₂SO₈ + 2e^-, so 0.55mol of e^- is needed to convert all the H2SO4 to H2S2O8...
I've a generator 12V, measured 0.5A = 0.18mol of e^- per hour, I want to transfer 1.3mol of e^- so 7 hours are needed...