Benzoic acid and p-nitroaniline are both organic compounds, but they have different solubilities in different solvents. Benzoic acid is more soluble in organic solvents such as diethyl ether, while p-nitroaniline is more soluble in water. This difference in solubility can be exploited to separate the two compounds using a process called liquid-liquid extraction.

Procedure

1. Prepare the mixture: Place a mixture of benzoic acid and p-nitroaniline in a separatory funnel.

2. Add the solvent: Add a suitable organic solvent, such as diethyl ether, to the separatory funnel. The solvent should be immiscible with water.

3. Shake the mixture: Shake the separatory funnel vigorously for several minutes to mix the two liquids thoroughly.

4. Allow the layers to separate: Let the mixture stand for a few minutes until the two liquids have separated into two distinct layers. The upper layer will contain the organic solvent and the benzoic acid, while the lower layer will contain the water and the p-nitroaniline.

5. Drain the lower layer: Carefully drain the lower layer, which contains the water and p-nitroaniline, into a beaker.

6. Repeat the extraction: Repeat the extraction process with fresh portions of the organic solvent until all of the benzoic acid has been extracted from the mixture.

7. Combine the organic extracts: Combine all of the organic extracts in a separatory funnel.

8. Wash the organic extracts: Wash the organic extracts with water to remove any traces of p-nitroaniline.

9. Dry the organic extracts: Dry the organic extracts over anhydrous sodium sulfate.

10. Evaporate the solvent: Evaporate the organic solvent from the extracts using a rotary evaporator or a heating mantle.

11. Collect the benzoic acid: The benzoic acid will be left behind as a solid.

By following this procedure, you can successfully separate benzoic acid from p-nitroaniline using liquid-liquid extraction.