In: Chemistry
EXTRACTION EXERCISE. The Kd (coeficient of distribution) between Dietilic eter and Water is 1.0 if 50mg of A is dissolve on 1.0ml of water. How much of A is going to be extracted in a portion of 0.50ml of dietilic eter? How much of A is going to remain on the water? Remember Kd=1.0
Let x mg of A be extracted in diethyl ether. Therefore, concentration of A per mL of ether is (x mg)/(0.50 mL).
Mass of A remains in water = (50.0 – x) mg; the concentration of A per mL of water is (50.0 – x) mg/(1.0 mL).
The partition co-efficient Kd is defined as
Kd = concentration of A in ether/concentration of A in water
===> 1.0 = (x mg/0.50 mL)/(50.0 – x)mg/1.0 mL
===> 1.0 = x/0.50(50.0 – x)
===> 1.0*0.50*(50.0 – x) = x
===> 25.0 – 0.5x = x
===> 1.50x = 25.0
===> x = 25.0/1.50 = 16.6667 ≈ 16.67
The mass of A extracted in ether is 16.67 mg (ans).
The mass of A remaining in the water layer is (50.0 – 16.67) mg = 33.33 mg (ans).