Question

Suppose solute A has a distribution coefficient of 1.0 between water and diethyl ether. Demonstrate that if 100 mL of a solution of 5.0g of A in water were extracted with two 25mL portions of ether, a smaller amount of A would remain in the water than if the solution were extracted with one 50-mL portion of ether.

Answer 1

Answer:

Explained

Explanation:

a) performing extraction of 25 ml of ether each time

K= 1= $\frac{\frac{5-x}{25} }{x/100}$

solving we get x= 4 g dissolved in water

5-x=1 g dissolved in ether

second extraction

K= 1 = $\frac{\frac{4-x}{25} }{x/100}$

solving this we get x= 3.2g dissolved in water

4-x= 3.2 g dissolved in ether

combining the two extractions 0.97 g of A extracted into ether that is 97% is extracted

b) performing one extraction 50% ether

distribution coefficient , K is the concentration of solute dilute to that to the solvent water

K= 1.0= $\frac{\frac{5-x}{25} }{x/100}$

solving we get

x= 3.33 g dissolved in water

and 5-x= 1.67 dissolved in ether