“Anthocyanins“ from the “Chemistry of plants“ set
Channel: MEL Chemistry
Date: 19/04/2018

Perform this amazing experiment at home with MEL Science: https://melscience.com/en/experiments/test-for-acids-or-bases-using-flowers/

Safety
* Put on protective gloves and eyewear.
* Conduct the experiment on the plastic tray.

Disposal
* Dispose of solid waste together with household garbage.
* Pour solutions down the sink.
* Wash with an excess of water.

Step-by-step instructions
1. Anthocyanins are the substances which give many flowers their color. They normally vary from red to blue. Anthocyanins dissolve in water, and even more easily if the water is hot.
2. Filter the crushed petals out of the solution.
3. Anthocyanins can change their colors depending on the acidity of the surrounding solution. If we add some acid salt, sodium hydrogen sulfate NaHSO₄, the solution will turn red.
4. Sodium carbonate Na₂CO₃, in turn, makes the solution more alkaline. If you add it slowly, drop by drop, you can see all the different colors the anthocyanin solution can have.
5. When the color stops changing, let the solution stand for some time. It will gradually turn yellow.