Question

In the extraction of salicylic acid from water using dichloroethane, a student begins with 2.0 g of the salicylic acid dissolved in 100 ml of water. After extraction with 20 ml of dichloroethane, drying and evaporation of the organic layer afforded 1.0 g of salicylic acid. Assuming the student was efficient and did not lose any material, what is the partition coefficient (K) for the system ?

Answer 1

Answer:

K = 5

Explanation:

Partial coefficient is also known as distribution coefficient, which is the ratio of  concentration of a solute in two immiscible liquids.

For given system we write it as:

Kd = $\frac{[salicylicacid]_{dichloromethane}}{[salicylicacid]_{water}}$

After extraction the concentration of salicylic acid in dichloromethane is 1g /20 mL = 0.05

Initially the amount of salicyclic acid present was = 2 g

out of this one grams was being extracted by organic solvent

The amount of solute remained in aqueous phase = 1 g

so the concentration of salicyclic acid in water = 1/ 100 = 0.01

Kd = $\frac{0.05}{0.01}=5$