Sciencemadness Discussion Board

H2SO4 cheap way?

Random - 6-7-2010 at 12:45

I found something in one book that could be interesting (it is old chemistry book of G. Francis):

Mixing citric acid with copper (ii) sulphate makes copper citrate. But what is the other product? Could it be H2SO4?


It looks false though because citric acid is a lot weaker than sulphuric...

[Edited on 6-7-2010 by Random]

bbartlog - 6-7-2010 at 15:36

Even if it works, I don't think citric acid (or copper sulphate for that matter) are all that cheap compared to sulfuric acid. If you think it's a neat experiment, have at it; but if you think it's economical I have to wonder what the prices look like where you are.
I have also seen a claim in an old book that oxalic acid will do this. The insolubility of the oxalate (and maybe the citrate, dunno) might allow the formation of copper oxalate and sulfuric acid to be favored, but I'm skeptical. In the case of citric acid, I know that calcium citrate is turned back into citric acid by addition of sulfuric acid, so I doubt the reaction runs the other way for copper.

BromicAcid - 6-7-2010 at 15:45

Reminds me of something I read once on making very pure sulfuric acid. The method was to mix a saturated solution of calcium sulfate with oxalic acid, and then filter off the calcium oxalate. On the plus side an excess of oxalic acid would 'burn up' on concentration. On the minus side look at the solubility of calcium sulfate ;)