A mixture contains water, propanone and dissolved salt.
| Substance | Boiling point (∘C^\circ\mathrm{C}∘C) |
|---|---|
| Propanone | 56 |
| Water | 100 |
| Salt | 1465 |
Propanone and water mix completely.
Which method gives a pure sample of propanone and a pure sample of salt?
Filter to remove the salt, then use simple distillation to collect the propanone.
Use fractional distillation to collect the propanone, then crystallise the salt from the solution left.
Crystallise the salt from the mixture, then filter to collect the propanone as the filtrate.
Use chromatography to separate the propanone, then filter the solution to collect the salt.
51 exam-style questions on OCR GCSE Chemistry 2.1 Purity and separating mixtures, covering 2.1.1 Pure substances and melting point data, 2.1.2 Relative formula mass and empirical formula, 2.1.3 Formulations as useful mixtures, 2.1.4 Techniques for separating mixtures, and 2.1.5 Chromatography and Rf values. Each one has a worked solution and a mark scheme showing where the marks go.