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pickle_64
Jun8-08, 06:35 AM
Hi,
i recently constructed a hofmann apparatus at home out of pvc and had some trouble with it. Basically, once it is set up, i only get gas from one electrode, the other does nothing. H2SO4 is used as the electrolyte, and the is 12 volts at 4 amps being put through it, DC. are there any simple flaws i am over looking as i just want to keep the oxygen and hydrogen separate.

thanks, your help is greatly appreciated.

Borek
Jun8-08, 06:42 AM
What are your electrodes made off? Prehaps you have evolving gas on one side and you dissolve electrode on the second?

Borek
--
http://www.chembuddy.com
http://www.ph-meter.info

pickle_64
Jun8-08, 07:07 AM
copper sheet metal in a coil.

Borek
Jun8-08, 08:52 AM
Very likely that you are dissolving copper. If so, solution will become bluish.

pickle_64
Jun8-08, 09:07 AM
why would this stop the 2nd gas being released?

Borek
Jun8-08, 09:35 AM
More or less you have

Cu -> Cu2+ + 2e

oxidation reaction instead of

2H2O -> O2 + 4H+ + 4e

Borek
--
http://www.chembuddy.com
http://www.ph-meter.info

pickle_64
Jun8-08, 09:43 AM
Thanks for that, i thought copper would have worked and no other site would tell me properly. on the subject, do you know of any suitable metals for use in this situation that wouldn't set me back a heap?

Borek
Jun8-08, 10:09 AM
Unfortunately the best I can think off is oplatinum - rather expensive. Carbon electrodes will be much cheaper, but don't ask me about details, as I don't know too much about them.

pickle_64
Jun8-08, 11:02 PM
thanks for the help