Tools: 250 ml flask, stopper
Chemicals: sodium hydroxide, glucose (you can buy at the drugstore as grape sugar), methylene blue
In 100 ml of water was dissolved 2 g of sodium hydroxide and 2 g of glucose. to a solution of
add 4 ml of 0.1% solution of methylene blue.
The flask with a rubber stopper.
Blue solution for a few minutes completely decolorized.
When shaking reappear blue color of the solution.
The phenomenon is caused by oxidation and reoxidation of methylene blue (her ox-form is colorless, redox-form
If there is no convincing attempt, just for a moment uncork the flask (flask with
gets oxygen), stopper and again is repeated.