Final answer:
When gently shaking a separatory funnel containing an amine with ether and aqueous HCl, the amine will react with HCl to form a water-soluble amine salt, which will then be found in the aqueous layer.
Step-by-step explanation:
If you gently shake a separatory funnel containing an amine with ether and aquous HCl, the amine will primarily be found in the aqueous layer. This is because amines will react with strong acids like HCl to form amine salts, which are water-soluble. Upon shaking the separatory funnel, the amine reacts with the hydrochloric acid in the aqueous layer to form an amine hydrochloride salt. Because this salt is more soluble in water than in ether, it will preferentially dissolve in the aqueous layer, leaving the ether layer with other substances.
The underlying principle guiding this separation is exploitation of the compounds' differing affinities for the solvents used based on their solubility and chemical reactivity. Amines generally have a higher solubility in water when converted to their salt form. The shaking process allows the amines to come into contact with the aqueous hydrochloric acid solution, facilitating this reaction. After which, when allowed to settle, the two immiscible liquids: ether and the aqueous amine salt solution, separate into two distinct layers that can be conveniently drawn off.