Author Question: Suppose you added an additional 50 ml of water to a separatory funnel containing a compound ... (Read 30 times)

CharlieWard · **on:** Aug 23, 2018

Suppose you added an additional 50 ml of water to a separatory funnel containing a compound distributed between 50 mL of ether and 50 mL of water. (The compound you want is
more soluble in ether than it is in water.) How will this addition affect
(a) the distribution coefficient of the compound?
(b) the actual distribution of the compound?

Question 2

The distribution coefficients for a compound are:benzene-water
, K = 5.5
petroleum ether-water, K = 5.0
methylene chloride-water, K = 1.0
Which is the best choice of solvent for extracting the compound from an aqueous reaction mixture? Explain your answer.

reelove4eva · **Reply #1 on:** Aug 23, 2018

Answer to Question 1

(a) The distribution coefficient is a constant. It is a ratio of the concentrations in the immiscible
two solutions; therefore, it would not change.
(b) The actual distribution of the amount of material in the two layers would change. More of
the compound would be retained in the water.

Answer to Question 2

From the distribution coefficients alone, benzene-water would be the best choice. However,
benzene is a carcinogen, and therefore petroleum ether-water with a slightly lower distribution coefficient would be the best choice.