Acid–base indicators – litmus, phenolphthalein, red cabbage, universal indicator

Integrated ScienceChemical ReactionsAges 13–14

Nine test tubes contain lemon juice, vinegar, HCl, distilled water, salt water, soapy water, baking soda, NaOH and limewater. Students dip litmus paper or add phenolphthalein, red cabbage juice or universal indicator and observe the color, place each solution on the pH scale and classify it as acidic, neutral or basic. A summary table records the color of every solution with all four indicators.