Make thymolphthalein indicator solution by dissolving 0.1 g thymolphthalein in 50 mL of ethyl alcohol. Add 50 mL water. Make baking soda solution by mixing 1 g of baking soda per 100 mL of water. 4. Make washing soda solution by mixing 1 g of washing soda per 100 mL of water. A safe way to find out if a substance is an acid or base is to use an indicator.
Indicators are a group of compounds that change color when added to acids or bases.
The color change indicates whether a substance is an acid or base. We are going to begin our work with indicators that are made from natural objects like red cabbage juice. We will also use chemical paper indicators called pH paper, litmus paper, and chemical solution indicators called phenolphthalein and thymolphthalein. Organize your students in small groups and give each group a recording chart. Identify the test substances and point out potential dangers.