Discussion in 'Supporting Chemistry' started by clairelucas, Jul 13, 2018.

  1. Silly question... how long does 20vol H2O2 last for? If I make some fresh now, will it still be ok ( or even mostly ok) to make O2 in a boiling tube on Monday? Or will I have to make it fresh...
    Shouldn't be a problem , but expecting to be in a meeting prior to the expt period, might be a push...
  2. If you want a guarantee for it to work then it should be prepared fresh. It won't take you a couple of minutes to do a !:5 dilution of your 100 vol Stock solution.:)
    clairelucas likes this.
  3. Ours usually lasts about a week but can be a bit slow. can you make it up and then make the oxygen before your meeting? id have thought a bunged tube of oxygen would last?
  4. Sorry, should have specified, it's for a practical to make O2, not for me to make O2 for them...
  5. Techitude

    Techitude COMMITTEE

    The longer you keep it the weaker it will eventually become but for something like making O2 when the concentration isn't particularly crucial it should be fine. We test any stock solutions before we send them out to make sure they give the desired results, have found H2O2 actually lasts longer than you'd expect. Hope that helps.
    clairelucas likes this.
  6. Yeah, we keep ours pretty cold and it lasts pretty well. I test it every year and even the low concentrations stay high enough to be usable for something.
  7. Still working well... shouldn't have worried!
    emarie73 likes this.