Partition coefficient: To determine partition coefficient of benzoic acid between benzene and distilled water.

To determine partition coefficient of benzoic acid between benzene and distilled water.

1. Experiment 10 To determine partition coefficient of benzoic acid between benzene and distilled water. SRP: Partition Coefficient 1

2. SRP: Partition Coefficient 2 When a solute is shaken with two immiscible solvents it gets distributed between the solvents. This distribution of solute in two solvents depends upon the solubility of the solute in two solvents. At the distribution equilibrium, the ratio of concentration of the solute in the two solvents is constant at a given temperature. The constant is called the partition coefficient (K) or the distribution coefficient of the solute between the two solvents To determine the partition co-efficient of benzoic acid between benzene and water.

3. SRP: Partition Coefficient 3 REQUIREMENTS: Chemicals : Saturated solution of benzoic acid in benzene Benzene 0.01N NaOH 0.1N NaOH Distilled water Apparatus : Separating funnel: 250 ml, Conical flask, Pipette, Burette and Stoppered bottles Separating funnel Conical flask Pipette Burette Stoppered bottles

4. SRP: Partition Coefficient 4 PROCEDURE: Prepare the following mixtures in separating funnels: Set I: 25ml water + 25 ml of saturated solution of benzoic acid in benzene Set II: 25 ml water + 20 ml saturated solution of benzoic acid in benzene + 5 ml benzene Set III: 25ml water + 15 ml saturated solution of benzoic acid in benzene + 10 ml benzene Shake the mixture in the separating funnel vigorously for about 30 minutes so that the benzoic acid gets distributed between the two solvents and the distribution equilibrium is reached. Allow the flasks to stand for 10 minutes to separate into two clear layers (remove the stopper of the separating funnel and keep its mouth open during this period to facilitate the separation). Drain off the lower aqueous layers in 3 different stoppered dry bottles. (Discard the intermediate layer between the two phases). Benzene layer remains in the separating funnels. Using a dry pipette take 5 ml of organic layer (Benzene) into a conical flask containing 10ml of water and titrate against 0.1 N NaOH using TCI FEP Fluoropolymer Films FEP Films for Chemical, Electrical, Composite Molding, & Medical Applications & Industries Ads by Stop seeing this ad Why this ad? We'll try not to show that ad again Ad closed by TCI FEP Fluoropolymer Films FEP Films for Chemical, Electrical, Composite Molding, & Medical Applications & Industries TCI Contact Us Ads by Stop seeing this ad Why this ad? We'll try not to show that ad again Ad closed by phenolphthalein as an indicator. End point: Colorless to pink.Pipette out 10 ml of the aqueous layer using a dry pipette and titrate it against 0.01 N NaOHsolution using phenolphthalein as an indicator. End point will be colorless to pink.

5. SRP: Partition Coefficient 5

6. SRP: Partition Coefficient 6 Similarly calculate concentration of benzoic acid in aqueous layer of sets II and III. Similarly calculate concentration of benzoic acid in aqueous layer of sets II and III.

7. SRP: Partition Coefficient 7

8. SRP: Partition Coefficient 8 Reference: More HN, Hajare AA. Practical Physical Pharmacy, Career publications, 2010: 73-76.