The table shows the colours of three indicators at different pH values.
| Indicator | Colour below the lower pH | Colour change happens between pH | Colour above the higher pH |
|---|---|---|---|
| Methyl orange | red | 3.1 and 4.4 | yellow |
| Bromothymol blue | yellow | 6.0 and 7.6 | blue |
| Phenolphthalein | colourless | 8.2 and 10.0 | pink |
A student tests a solution with each indicator.
What is the pH of the solution?
Between 3.1 and 4.4
Between 4.4 and 6.0
Between 6.0 and 8.2
Between 7.6 and 8.2
112 exam-style questions on OCR GCSE Chemistry 3.3 Types of chemical reactions, covering 3.3.1 Oxidation and reduction in terms of oxygen, 3.3.2 Acids, alkalis and neutralisation, 3.3.3 The pH scale and measuring pH, 3.3.4 Oxidation and reduction in terms of electrons, 3.3.5 Dilute and concentrated, weak and strong acids, and 3.3.6 Hydrogen ion concentration and pH. Each one has a worked solution and a mark scheme showing where the marks go.