Question

4. The solubility of acetanilide in hot water is 5.5 g / 100 mL at 100oC and its solubility in cold water is 0.53 g / 100 mL at 0oC. What would be the maximum theoretical percent recovery from the crystallization of 2.5 g of acetanilide from 50 mL of water? Show the calculation.

Answer 1

Answer:

89,4%

Explanation:

If you have a solutio of 2,5g of acetanilide in 50mL of water and you warm this solution to 100°C you will dissolve all acetanilide because the maximum solubility in 50mL will be:

5,5g / 100mL → 2,75g / 50mL.

Then, if you cold the water to 0°C the solubility in 50mL will be:

0,53g / 100mL → 0,265g / 50mL.

That means you will precipitate:

2,5g - 0,265g = 2,235g of acetanilide

The theoretical percent recovery will be:

2,2365g / 2,5g ×100 = 89,4%

I hope it helps!