Sciencemadness Discussion Board

Reaction of lead dioxide with Mn2+ ions

Wrecking Bereserker - 3-4-2019 at 07:21

Im trying to react lead dioxide with Mn2+ ions in acid medium it doesn't work when using H2SO4 does it only work with Nitric acid?

First of all im kind of confused why do we add medium(acidic,base) for certain reactions to happen they don't usually do anything right?
For example when in acid medium H2O2 + KMnO4 becomes Oxygen and Mn2+ each other oxidize and reduce then why is there the medium?

Ubya - 3-4-2019 at 13:20

The acidic or basic environment is important for reactions to happen. The reaction you used as an example Is a redox reaction, and to balance it you need H+ or OH-.
H2O2→O2 + 2H+ + 2e- (neutral reduced side→(2+) +(2-)=0 neutral oxidized side)
MnO4- + 8H+ + 5e- →Mn2+ + 4H2O ( (1-)+(8+)+(5-)=2+ on the oxidized side, 2+ on the reduced side)
5H2O2 + 2MnO4- + 8H+ + 10e- →2Mn2+ +5O2 + 8H2O +10e-
SO4-- and K+ are spectators
5H2O2 + 2KMnO4 + 3H2SO4 → 5O2 + 2MnSO4 + K2SO4 + 8H2O

As you can see we need H+ to balance the equations and get the right charge in the half reactions

[Edited on 3-4-2019 by Ubya]