posted by david on .
The solubility of acetanilide in hot water (5.5 g/100 mL at 100C) is not very great, and its solubility in cold water (0.53 g/100 mL at 0C) is significant. What would be the maximum theoretical percent recovery from the first recrystallization of 0.5 g of acetanilide from 100 mL of water (assuming the solution is chilled to 0C)?
I might argue with the use of the words "not very great" and "significant."
How much H2O is needed to dissolve 0.50 g acetanilide? That's
100.0 mL x (0.5/5.5) = 9.09 mL.
How much will we lose on cooling that to zero C? That's
0.530 x (9.09/100) =0.048.
%recovery is (0.500-0.048)/0.500]*100 = ?