The pain reliever phenacetin is soluble in cold water to the extent of 1.0 g/ 1310 mL and soluble in diethyl ether to the extent of 1.0 g/90 mL. The distribution coefficient for phenacetin in these two solvents then, is 0.0167.
If 50 mg of phenacetin were dissolved in 100 mL of water, how much ether would be required to extract 90% of the phenacetin in a single extraction?