A student prepares a solution of zinc sulfate.
Which of the following describes the best way to obtain pure, large crystals of zinc sulfate from this aqueous solution?
Heat the solution gently to evaporate some water until a saturated solution forms, then leave it to cool.
Boil the solution rapidly with a strong Bunsen burner flame until all the water has evaporated.
Pour the solution through a filter funnel lined with filter paper and collect the residue.
Freeze the solution in an industrial freezer and then break the ice to retrieve the crystals.
