Home Cosmetic Science Talk General Science Hydrogen peroxide decomposition reaction

  • Hydrogen peroxide decomposition reaction

    Posted by Ichlas on January 23, 2020 at 1:11 am

    I was wondering what is hydrogen
    peroxide decomposition reaction? why is it resulting an acidic solution
    (decreasing the pH from the initial pH) as they decompose over time.

    Ichlas replied 4 years ago 3 Members · 3 Replies
  • 3 Replies
  • EVchem

    January 23, 2020 at 2:14 pm

     2 H2O2 —UV/heat/time-> 2 H2O + O2

    Hydrogen peroxide is a weak acid, that’s why the solution becomes acidic. This is more of a general chemistry question though that you could easily learn more about by googling

  • pharma

    January 23, 2020 at 8:54 pm

    EVchem said:

    …Hydrogen peroxide is a weak acid, that’s why the solution becomes acidic…

    Reason has it that this would mean it becomes alkaline since the acid (H2O2) decomposes ;) .

    I don’t have a definite answer but a guess: It might be stabilisers which causes the effect. H2O2 is often stabilised with a small amount phosphoric acid. Once O2 has gassed out, volume goes down and, because it’s lacking a buffer, even that small a change leads to a noticeable drop in pH.

  • Ichlas

    January 24, 2020 at 2:23 am

    @Pharma that totally makes sense. thank you so much for the answer 🙂

Log in to reply.