A laboratory supplier claims that an orange reference substance is pure. The same sample was analysed by paper chromatography using three different solvents.
| Solvent | Number of spots produced |
|---|---|
| R | 1 |
| S | 1 |
| T | 1 |
Explain why the complete set of results gives stronger evidence that the substance is pure than the result using solvent R alone.
Describe a result using a fourth solvent that would cause the supplier to reject the claim that the substance is pure.
113 exam-style questions on AQA GCSE Chemistry 8.1 Purity, formulations and chromatography, covering 8.1.1 Pure substances, 8.1.2 Formulations, and 8.1.3 Chromatography. Each one has a worked solution and a mark scheme showing where the marks go.