Question

Question regarding an extraction lab involving benzoic acid, azobenzene, and m-nitroaniline and adding NaOH, HCl, and saturated sodium chloride solution all using a separatory funnel.

Why do we need to add the drying agent to the organic layer? What are you removing? Why do we need to add acid to the carboxylic acid flask? Why do we add base to the amine flask? What are we precipitating?

How do you improve the purity of the recovered solids?

Answer 1

To remove the moisture (water) from the organic layer, we need to add drying agent.

We remove the moisture or traces of water from the organic layer.

During the extraction process, we convert the acid to its sodium salt. Once, we separate the acid layer from the other parts, we add acid to generate neutral the carboxylic acid.

In the extraction, process, the amine is converted to its ammonium salt and to generate the neutral amine, we add base.

We are precipitating the benzoic acid or amine.

The purity can be improved by recrystallization.