"Manganese traffic light" experiment
How to make liquid to change it's color 3 times
Chemical traffic lights are series of experiments in which light changes in the course of an oxidation-reduction reaction. You can do this experiment at home,observing safety rules.
Reagents and equipment:
- three glasses;
- potassium permanganate;
- sugar (sucrose);
- sodium hydroxide;
- distilled water.
Dissolve several potassium permanganate crystals in 300 ml of water. Then dissolve 10 g of sugar and 0.5 g of sodium hydroxide in 50 ml of distilled water. Mix the solutions of sugar and sodium hydroxide. Pour the resulting mixture into the solution of potassium permanganate. Observe the change of color from pink to green to yellow. If you wish to conduct the experiment at home, you can use liquid for cleaning pipes instead of the sodium hydroxide solution.
Potassium permanganate is a strong oxidizer, as the manganese atom has a degree of oxidation of +7, and depending on the medium the permanganate ion can reduce to differing degrees of oxidation. In an alkaline medium, the permanganate ion reduces to a manganate ion with a degree of oxidation of manganese +6, the aqueous solution of which has a green tint. The manganite ion then reduces to manganese oxide (IV), which is brown, but as it is present in the solution in the form of tiny particles, the solution turns yellow.
Wear gloves and protective glasses when working with alkaline solutions, as they may cause severe burns.
Warning! Substances of this experiment are toxic and highly dangerous for your health. Do not try this at home. Only under professional supervision.