MnO₄⁻ + 8 H⁺ + 5 e⁻ → Mn²⁺ + 4 H₂OHalf equation for reduction in an acid medium.
Use when: In other environments, products may change.
Permanganate titrations
Use permanganate to dose a reducing agent by electron exchange.
What is happening?
In an appropriate acidic medium, permanganate is reduced to Mn²⁺ while the measured species oxidizes. Its color makes it possible to identify a slight excess of titrant.
The number of electrons exchanged sets the proportions of the titration. Iron(II), oxalate and hydrogen peroxide do not all have the same stoichiometry or the same kinetics.
The formulas, with their conditions.
MnO₄⁻ + 5 Fe²⁺ + 8 H⁺ → Mn²⁺ + 5 Fe³⁺ + 4 H₂O1 mol of permanganate for 5 mol of iron(II).
Use when: Example of titration, not universal relationship for any reducer.
Where is this principle used?
Steel laboratory
Determine iron contents using a validated method.
Oxidizing products factory
Check a hydrogen peroxide solution.
What to observe in the experiment
Compare two iron(II) samples of the same volume but different concentrations. Predict the direction of variation of the equivalent volume.
References and readings
This sheet explains the principles and their assumptions. Educational simulation can simplify the process; an industrial model requires suitable data and validation.
Have you understood the essentials?
Only one correct answer per question. Answer all three questions, then view the answer key.
Intu Lab · Understanding sheet · Kimba Christian