The table below lists four key stages in the purification of an impure sample of benzoic acid by recrystallisation.
| Stage | Process |
|---|---|
| 1 | Filter the crystals under reduced pressure using a Büchner funnel, wash with a small volume of cold solvent, and dry. |
| 2 | Dissolve the impure solid in the minimum volume of hot solvent. |
| 3 | Cool the filtrate slowly to room temperature and then in an ice bath to allow the product to crystallise. |
| 4 | Perform a rapid hot gravity filtration of the solution to remove insoluble impurities. |
Which is the correct order for the stages?
2, 3, 4, 1
2, 4, 3, 1
4, 2, 3, 1
2, 4, 1, 3
8 exam-style questions on OCR GCSE Chemistry Practical skills. Each one has a worked solution and a mark scheme showing where the marks go.