Hydrogen peroxide

[jacknife360]

How does hydrogen peroxide (~ 30%) act as an oxidising agent (Co2+ --> Co3+), while at the same time a producing a gas (I assume it's oxygen)? This all happens in acidic solution. I can see how it works if it's in alkaline solution.

 

Thanks for any help.

[Tartaglia]

H2O2 +2H+ +2e --> 2H2O (H2O2 acting as an oxidant)

H2O2 --> 2H+ +2e +O2 (H2O2 acting as a reductant)

 

O2 should be released when H2O2 acts as a reductant, but loads of transition metals catalyse the decomposition of H2O2 and that is where the O2 comes from

 

H2O2 --> H2O +1/2O2

[jacknife360]

But the H2O2 oxidised the Co 2+ to Co 3+, as well as effervescing. Maybe two simultaneous reactions involving Hydrogen peroxide

 

a decomposition to oxygen and water

 

and H2O2 acting as oxidising agent.

 

Thanks for your help

[Tartaglia]

The Co3+ will catalyse decomposition

 

H2O2 +2Co3+ --> O2 + 2Co2+ +2H+

 

The Co2+ will then be reoxidised

 

H2O2 + 2Co2+ + 2H+ --> 2H2O + 2Co3+