Question #8fd8b

1 Answer
Feb 22, 2017

Answer:

Recrystallize the mixture from hot water.

Explanation:

The solubility of acetanilide in hot water is 5.5 g/100 mL at 100 °C

and 0.53 g/100 mL at 0 °C.

Urea is highly soluble in water (108 g/mL at 20 °C).

Assume that you have a mixture containing 5.5 g of acetanilide and 5.5 g of urea.

Boil the mixture with 100 g of distilled water and perhaps some activated charcoal and filter through a fluted filter paper.

Cool the filtrate in an ice bath to 0 °C.

The urea will remain in solution, while beautiful colourless plate-like crystals of acetanilide will precipitate out.

Acetanilide crystals
(From flickrhivemind.net)

You can then remove the pure crystals by suction filtration.

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