Preparing red cabbage indicator
The juice of red cabbage contains a natural pH indicator that changes colour according to the acidity of the solution.
Red cabbage contains a pigment called flavin which is also found in apple skins, plums and grapes.
Very acidic solutions turn anthocyanin into a red colour.
Neutral solutions will result in a purplish colour.
Basic solutions turn into in greenish-yellow.
The pH of a solution can be determined based on the colour that it turns the anthocyanin pigments in red cabbage juice.
Making red cabbage indicator: