Redox titration with KMnO₄ template

Burette of KMnO₄ in a burette clamp on a stand, over a conical flask of acidified iron(II) solution on a white tile; oxalic acid variant warmed to about 60 °C. A-level / AP / IB / CBSE.

What the template shows

• KMnO₄ is its own indicator: stop at the first permanent pink
• White tile
• End point: first pale pink that lasts 30 s
• KMnO₄(aq) in the burette
• e.g. 0.0200 mol dm⁻³. Too dark to see through, so read the top of the meniscus
• The purple colour vanishes as it meets the flask; go dropwise near the end
• 25.0 cm³ by pipette with excess dilute H₂SO₄ (not HCl, which MnO₄⁻ oxidises). MnO₄⁻ + 8H⁺ + 5Fe²⁺ → Mn²⁺ + 5Fe³⁺ + 4H₂O
• Oxalic acid variant
• Warm the acidified acid to about 60 °C first; the Mn²⁺ formed catalyses the reaction, so the first drops fade slowly
• Reaction setup

Drawn with 12 shapes – every one editable in MolDraw.

Sources

• Housecroft & Sharpe, Inorganic Chemistry, 5th ed., Pearson 2018 Textbook