Chameleon
Objective: Change the colour of a solution with a lollipop
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Laboratory materials
100 mL plastic beaker
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Reagents
Potassium permanganate (KMnO4)
Sodium hydroxide (NaOH) 0.015 M
Lollipop
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Safety
Don't forget the gloves, lab coat, and safety goggles!!!
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Questions
Which colors have you seen?
Why is the solution color changing?
Procedure
- Dissolve a spatula tip (see image below) of potassium permanganate in 100 mL of sodium hydroxide solution.
- Stir this solution with a lollipop and observe what happens.
Theoretical explanation
In the experiment, a chemical reaction called redox takes place. During this process, potassium permanganate is being reduced, and the sugar in the lollipop is being oxidized. In other words, sugar is giving some of its electrons to the manganese salt. The reduction occurs in several steps, and in each step, manganese exhibits a different color. In the first step, the purple potassium permanganate is reduced to green manganate. Initially, the solution appears blue because both compounds coexist. Finally, the manganate is further reduced to manganese dioxide, which is orange. Sodium hydroxide is used as a base to facilitate all these redox reactions.
