Question

Problem 1

The distribution coefficient of phthalic acid distributed between water and diethyl ether at 25 C is 0.59

mass fraction in water (aqueous phase) per mass fraction in the diethyl ether phase. Twenty-five gram of

pure diethyl ether is added to 110 g of a mixture containing 91 wt% water and phthalic acid and the

resulting blend is allowed to equilibrate. Assuming that diethyl ether and water are immiscible

a. Draw and completely label a flowchart for this system.

b. Calculate the percentage composition of phthalic acid in water and diethyl ether

Answer 1

a. The flow diagram is shown below.

b. D = 0.59 = phthalic acid in water phase/phthalic acid in ether phase

total mass = 110 g

mass of water = 100.1 g

mass of phthalic acid = 9.9 g

mass of diethylether = 25 g

let x be the amount of phthalic acid in ether phase and 100 ml of diethylether added for extraction

0.59 = (x/100.1)/(9.9-x/25)

0.234 - 0.0236x = 9.99 x 10^-3x

0.03359x = 0.234

x = 7.00 g

So we have 7.00 g of phthalic acid in ether phase and 2.9 g of phthalic acid in the aqueous phase.