hello i'm doing a redox stoichiometry lab having to do with titration
6H +5H2O2 + 2MnO4 -- 5O2 + 2Mn2+ + 8H2O
Why is H2O2 the source of O2 product in this titration?
The O in H2O2 changes oxidation state from -1 for each oxygen on the left to 0 for each O atom on the right (in O2). The O in MnO4^- is -2 on the left and it is -2 on the right (in H2O) and it doesn't change; therefore, that oxygen is not involved in the redox process other than the production of H2O.
In this titration, hydrogen peroxide (H2O2) acts as the source of oxygen gas (O2) because hydrogen peroxide can easily decompose into water (H2O) and oxygen gas (O2). This reaction is known as a redox reaction, where the hydrogen peroxide is oxidized (loses electrons) and the permanganate ion (MnO4-) is reduced (gains electrons). The balanced equation for this reaction is:
6H+ + 5H2O2 + 2MnO4- → 5O2 + 2Mn2+ + 8H2O
Here's a step-by-step explanation of why hydrogen peroxide is the source of the oxygen gas in this titration:
1. Oxidation of Hydrogen Peroxide:
In the reaction, each H2O2 molecule is oxidized. Oxygen (O) has a 2- oxidation state in H2O2, but it has a 0 oxidation state in O2 gas. So, hydrogen peroxide loses two electrons during the reaction.
2H2O2 → 2H2O + O2
2. Reduction of Permanganate Ion:
The permanganate ion (MnO4-) is reduced to manganese(II) ion (Mn2+) during the reaction. Permanganate has a +7 oxidation state, while manganese has a +2 oxidation state.
MnO4- + 8H+ + 5e- → Mn2+ + 4H2O
3. Overall Equation:
Combining the oxidation of hydrogen peroxide and the reduction of permanganate, we get the balanced overall equation:
6H+ + 5H2O2 + 2MnO4- → 5O2 + 2Mn2+ + 8H2O
Therefore, hydrogen peroxide acts as the source of the oxygen gas in this titration because it undergoes oxidation, releasing oxygen gas in the process.