The distribution coefficient between ether & water for aspirin at room temperature is 3.5. What weight of aspirin would be extracted by a single extraction with 150 ml water from a solution of 10 gms of aspirin in 100 ml ether? Calculate the weight of aspirin which would be removed by three extractions with 50 ml portions of water.

Answer 1

x = wt aspirin in ether
10-x = st aspirin in H2O layer.

3.5 = (x/100)/(10-x/150
Solve for x and 10-x

Answer 2

7.5