An amazing reaction that can do it in home with household chemicals. The main ingredient methylene blue can be bought from aquarium shops.
- Methylene blue is a medication and dye. Also used in aquariums for prevention of fungal infection. It is a safe chemical(low concentrations).
- Sodium hydroxide is corrosive. Be careful when handing corrosive chemicals.
- This blue bottle reaction is a color changing redox reaction.
Chemicals and Equipment
- 2 g – sodium hydroxide
- 4 g – glucose
- 1 ml – methylene blue
- 200 ml – water
- 100 ml beaker
- 250 ml conical flask
- 1 rubber stopper/cork
How to do the experiment
- First dissolve sodium hydroxide in 100 ml of water and add the solution to conical flask.
- Dissolve glucose in 100 ml of water and add to the conical flask.
- Now add 1ml of methylene blue.
- Shake the flask well until solution become blue then keep the solution without shaking to become colorless.
- You can repeat this experiment several times.
What Happened ?
A redox reaction is happened during the experiment. Reaction happens in a basic medium. That is why sodium hydroxide is added to the solution. Active reactants are methylene blue and glucose. Methylene blue is a redox dye. That means it varies its color when dye is oxidized and reduced.
When solution is shaking methylene blue combine with oxygen in air and it oxidizes. Oxidized dye is blue color. This part happens fast. Then solution keeps to settle dye reduces. Reduced dye is colorless. This reaction is slow.However the color changing time depends on the temperature of solution and the concentration of methylene blue. When dye concentration is high, solution takes more time to become colorless. Temperature is high color changing happens quickly.