The chemical chameleon reaction is a two step reaction in which you can visualise various oxidation states of manganese starting with potassium permanganate (+7) and ending with manganese dioxide (+4). The reaction is performed in alkaline conditions using caster sugar as a reduction agent. In the first step of this reaction, the purple potassium permanganate is being reduced down to the green manganate ion. A mixture of these two compounds gives the solution a blue colour.
MnO4- + e- → MnO4-2
Next, the manganate ion is further reduced to manganese dioxide which is an orange colour.
MnO4-2 + 2H2O + 2e- → MnO2 + 4OH-
Potassium permaganate is a strong oxidiser and may cause fire when in contact with other materials. May be harmful if swallowed, and may cause severe respiratory tract irritation with possible burns. Causes severe eye and skin irritation. Causes severe burns and gives out heat when added to water. Always wear gloves when handling these two chemicals.Materials and Equipment
Materials and Equipement
- Potassium permanganate
- Sodium Hydroxide
- Caster sugar
- Add a few potassium permanganate crystals to 5ml of water. Agitate until dissolved. The more concentrated the solution the less likely you will be able to see the colour change from purple to green, but the orange manganese dioxide will be more visible.
- To 100ml of water, add 1.5g of sodium hydroxide and 1g of caster sugar. Agitate the soultion until both have dissolved.
- Add a small amount of the potassium permanganate solution to the caustic sugar solution and agitate.