An unlabelled potassium compound is either potassium carbonate or potassium hydroxide. The formula of potassium carbonate is K2CO3\mathrm{K_{2}CO_{3}}K2CO3.
A technician tests a sample of the compound.
| Test | Observations |
|---|---|
| Dilute nitric acid, HNO3\mathrm{HNO_{3}}HNO3, is added to the sample. The gas produced is passed through limewater. | The mixture fizzes. The limewater turns milky. |
Potassium ions are K+\mathrm{K^{+}}K+ and nitrate ions are NO3−\mathrm{NO_{3}^{-}}NO3−.
Explain which potassium compound was tested.
Write a balanced symbol equation for the reaction in the test.
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.