Question

If you have 5.15 g of caffeine dissolved in 92.8 mL of water and the extraction coefficient between H2O and CH2Cl2 is 21.51. How many grams of caffeine will extract into the CH2Cl2 layer if you use 61.5 mL?

Answer 1

given K= extraction coefficient between H2O and CH2Cl2

there are 21.52 gm of caffeine in 100 gm of   CH2Cl2 and 1 gm of Caffeine in 100 gm of water

K= 21.51

let x= mass of Caffeine in CH2Cl2, 5.15-x= mass of caffeine in water

Hence x/61.5/(5.15-x)/92.8 = 21.51

x/61.5= 21.51*(5.15-x)/92.8

92.8x= 61.5*21.51*(5.15-x)=1323*(5.15-x)

x*(92.8+1323)= 1323*5.15

x= 4.81

4.81 gm of caffeine will be there in CH2Cl2 and 5.15-4.81=0.34 gm of Caffeine will be there in water.