Question

To separate a mixture of benzoic acid and fluorene, we are going to use an acid-base extraction technique. Most carboxylic acids are insoluble or slightly soluble in water, but they are highly soluble in dilute aqueous sodium hydroxide because the organic acid reacts with the base and produces carboxylate ions, a polar species. In a mixture of a carboxylic acid and an organic compound, the acid may be selectively removed from an organic solvent by extracting with a dilute NaOH solution. After separating the organic and aqueous layers, the carboxylic acid may be recovered from the aqueous solution by adding HCl, which causes precipitation of the carboxylic acid. Draw two structures below.

Answer 1

Answer: please find attached to see the structure.

1. THE STRUCTURE OF BENZOIC ACID AND FLUORENE, soluble in ether and insoluble in water.

2. THE STRUCTURE OF CARBOXYLIC ACID BEEN EXTRACTED.

Explanation: the mixture of benzoic acid and fluorene are the first diagrams which shows the carboxylic acid attached to the benzene ring, which are soluble in ether and insoluble in water. When dissolved in NaOH(aq) is the carboxy ion becomes soluble in water but insoluble in ether, this is seen in the second diagram.

The third diagram shows the carboxylic acid been precipitated and soluble in ether but insoluble in water.

NOTE THE TWO MAIN DIAGRAM IS THE FIRST AND THE LAST DIAGRAM, WHERE CARBOXYLIC ACID DISSOLVES IN AQUEOUS SODIUM HYDROXIDE, AND WHEN THE ACID IS BEEN PRECIPITATED IN AQUEOUS HCl.

ALSO NOTE THE CHANGE IN BENZOIC RING MIXED WITH FLUORENE TO THAT OF THE ACID BEEN EXTRACTED.

Hope together with the picture, this has helped you.