Red cabbage extract can indicate whether a substance is an acid (like vinegar) or a base (like ammonia). It can also show how strong an acid or a base a substance is. Chemists use the pH scale to express how acidic (like an acid) or basic (like a base) a substance is. A pH value below 7 means that a substance is acidic, and the smaller the number, the more acidic it is. A pH value above 7 means that a substance is basic, and the larger the number, the more basic it is. Red cabbage extract has different colors at different pH values. These colors and approximate pH values are:
approximate pH: Code
2 4 6 8 10 12
color of extract: red purple violet blue blue-green green
