Titration of KMnO4 and H2O2 under Acidic Conditions

Click For Summary
SUMMARY

The discussion centers on the redox titration of potassium permanganate (KMnO4) with hydrogen peroxide (H2O2) under acidic conditions. The key conclusion is that before reaching the equivalence point, the solution becomes colorless and oxygen gas (O2) is produced. The reduction potentials for H2O2 and KMnO4 are +1.78 V and +1.51 V, respectively, indicating that H2O2 acts as the oxidizing agent in this reaction. The discussion highlights the importance of considering pH and formal potentials in redox reactions.

PREREQUISITES
  • Understanding of redox reactions and titration principles
  • Knowledge of reduction potentials and their significance
  • Familiarity with acidic conditions and their effects on chemical reactions
  • Basic grasp of the chemical behavior of KMnO4 and H2O2
NEXT STEPS
  • Study the impact of pH on reduction potentials in redox reactions
  • Research the formal potentials of H2O2 and KMnO4 under varying acidic conditions
  • Learn about the stoichiometry of redox titrations
  • Explore the mechanisms of gas evolution in redox reactions
USEFUL FOR

Chemistry students, laboratory technicians, and educators involved in analytical chemistry and redox titration experiments.

watermarked
Messages
4
Reaction score
0

Homework Statement


A redox titration is carried out by adding Purple KMnO4 solution from a burette to a solution of H2O2 in a flask. Which of the following would occur in the flask before the equivalence point is reached?

The answer is: The solution is colorless and O2 is formed.
The other options were that the solution would remain purple and O2 gas would form, that the solution would remain purple and H2 gas would form, and the solution would be colourless and O2 gas would form.

Homework Equations


So my table says:
H2O2 + 2H+ + 2e- <=> 2 H20 has a reduction potential of +1.78
And Mn04 + 8H= + 5e- <=> Mn2+ + 4H20 has a reduction potential of +1.51

The Attempt at a Solution


Shouldn't H2O2 be the oxidizing agent, forming H2O?
 
Physics news on Phys.org
First of all, potentials you listed are for standard conditions and they are strongly pH dependent. This titration takes place in a very low pH, have you tried to estimate formal potentials in the solution?

watermarked said:
Shouldn't H2O2 be the oxidizing agent, forming H2O?

And what would get oxidized in the process?

But the most important part is, there is another reaction taking place at 0.70V.
 
No -- since the question only mentions that it takes place under "acidic conditions", I assumed it was under standard acidic concentrations. I guess that assumption was wrong, since it isn't one of the options.

Thanks for your help.
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
23K
Replies
5
Views
24K
  • · Replies 5 ·
Replies
5
Views
10K
Replies
1
Views
4K
  • · Replies 1 ·
Replies
1
Views
28K
  • · Replies 3 ·
Replies
3
Views
4K
Replies
1
Views
6K
  • · Replies 3 ·
Replies
3
Views
8K
Replies
5
Views
7K
  • · Replies 2 ·
Replies
2
Views
9K