Think back when you did an extraction in college. You needed 2 phases.....an organic phase....which was the ether.......you then added either AQUEOUS acid or base, to complete your procedure. If you had water and ethanol......only one phase would be present. Say you dissolved benzene, toluene , benzoic acid, and aniline in ether.........you would then add aqueous KOH for example.....this would react with the benzoic acid and create the aqueous layer.. sodium benzoate would be produced......which if you recall.....would be a distinct layer in the separatory funnel.
