Why can hydrogen peroxide act as both an oxidising agent and a reducing agent?

Hydrogen peroxide has the ability to gain or lose electrons, as its oxygen atoms are in the -1 oxidation state. By gaining electrons they can go to the -2 oxidation state, and by losing electrons they can go to the zero oxidation state (the element)

When someting acts as an oxidising agent is gains electrons (removing them from the oxidised species). This can be shown by the relevant half-equations:

H2O2 + 2e –> 2OH

or in the presence of acid:

H2O2 + 2H+ + 2e –> 2H2O

How is the volume measurement of hydrogen peroxide related to its molarity?

May 21st, 2007

Hydrogen peroxide decomposes according to the equation: 2H2O2 –> 2H2O + O2
If you start with 100 volume H2O2 then 1 dm3 of solution will release 100 dm3 oxygen (at RTP)
This means that 1 litre of H2O2 solution releases 100/24 moles of oxygen and as 2 moles of H2O2 decompose to release 1 mole of oxygen then there must be 2 x 100/24 moles of H2O2 in the solution
This is equal to 8.33 mol/dm3