Chameleon Reaction Experiment

The chameleon reaction experiment is an experiment in which a solution spontaneously changes colour several times due to the different oxidation states of potassium permanganate. In this experiment you can learn more about the phenomena of: redox reaction y pH.

MATERIALS

• Potassium Permanganate
• Sodium hydroxide
• Sugar

STEP-BY-STEP EXPERIMENT

1. Add 1 tablespoon of sodium hydroxide and 3 tablespoons of sugar to a beaker.
2. Add water to 150-175ml and stir well.
3. In another beaker, add a little potassium permanganate and add about 50 ml of water.
4. While the sodium hydroxide and sugar solution is being stirred, the potassium permanganate is added. In basic solution, it changes colour as it is reduced, going from violet with oxidation state +7, to green with oxidation state +6, K2MnO4, and then to oxidation state +4, MnO₂ brown in colour.

VIDEO EXPERIMENT

TECHNICAL EXPLANATION

In potassium permanganate, formula KMnO4, the permanganate has an oxidation state +7, violet in colour, it changes to a +6 oxidation state, green in colour, K2MnO4, and this to a +4 oxidation state, MnO4.₂ brown in colour.

KMnO₄ (violet) → K₂MnO₄ (green) → MnO₂ (brown / yellow suspension)

This reaction occurs in basic solutions (pH>7)together with a reducing agent. Sodium hydroxide, potassium hydroxide or any other hydroxide is added to alkalinise the solution. Different products could be used as reducing agents, the most common being sugars.