In a titration to determine the concentration of a potassium hydroxide solution, a student pipettes 25.0 cm³ of the alkali into a conical flask and adds a few drops of phenolphthalein indicator.
Dilute hydrochloric acid is slowly run in from a burette until the end point is reached.
State the colour change observed in the conical flask at the end point of this titration.
276 exam-style questions on Edexcel GCSE Chemistry 4.1 Acids, covering 4.1.1 Acids, alkalis and the pH scale, 4.1.2 Hydrogen ion concentration and pH, 4.1.3 Dilute and concentrated, weak and strong acids, 4.1.4 Bases, alkalis and the reactions of acids, 4.1.5 Chemical tests for hydrogen and carbon dioxide, 4.1.6 Neutralisation as a reaction of acids with bases, 4.1.7 Preparing soluble salts, and 4.1.8 Solubility rules and preparing insoluble salts. Each one has a worked solution and a mark scheme showing where the marks go.