Laboratory Practice1 Preparing and using red cabbage juice as an

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Laboratory Practice: Preparing and Using Red Cabbage Juice as an Acid-Base Indicator Introduction Chemical substances come in an almost endless variety. Two special types are acids and bases. They are complementary and, in a way, opposite to each other. They are found in nature and in relationship with water. Volcanic sulfuric acid lakes and alkaline natron lakes are examples of acids in the mineral world, but acids and bases are also found and are essential to living things: plants and animals. The growth of plants and the blood in our bodies are related to the equilibrium between acids and bases. Digestion of food in our bodies is also affected by the pH of certain digestive substances: stomach acid and bile. In this practice, we will prepare red cabbage juice and use it as a pH indicator. pH is a numerical value related to the strength of an acid or a base. Strong acids have a pH of 0, while strong bases have a pH of 14. The neutral value is 7. Substances with a pH of 7 are neither acids nor bases; they are neutral. You will learn how to use this pH indicator and elaborate a pH color scale by testing many substances that can be found at home, and even some stronger acids and...