Chemistry · Amines · NEET
An amine has a lone pair on nitrogen, so it is basic and reacts with the acid to form an ammonium salt (like R-NH3+ Cl-). This salt is ionic, so it dissolves in the water layer. The non-basic compound (a hydrocarbon or ester) has no basic site, so it does not react and stays in the organic (ether) layer. The two layers separate, and the amine is now in the water layer.
Add a strong base like NaOH to the water layer. NaOH takes the proton off the ammonium ion and regenerates the neutral amine. The free amine is not ionic, so it comes out of the water and can be collected (extracted into ether or separated as a layer). NCERT states: amine salts on treatment with a base like NaOH regenerate the parent amine.
The ammonium salt is ionic (it has a positive R-NH3+ ion and a negative Cl- ion), and ionic compounds dissolve well in water. A free higher amine is mostly a hydrocarbon-like molecule, so it is much less soluble in water and prefers the organic layer. Turning the amine into a salt is what pulls it into the water phase.
No. Non-basic compounds like alkanes, benzene, or esters have no lone pair that can accept a proton, so they do not form salts with dilute acid. They stay unchanged in the organic solvent layer. This difference in behaviour is exactly what makes the separation work.
The water layer. The amine becomes a water-soluble salt and moves into the aqueous acid layer. The non-basic compound remains in the ether (organic) layer. You separate the two layers, then add NaOH to the water layer to recover the pure amine.
Try the real previous-year questions from this chapter — each with the answer and a full solution.
Amines are basic and react with dilute acid to form salts that are soluble in water but insoluble in organic solvents like ether. Non-basic compounds do not react. This solubility difference is the basis of separation (directly stated in NCERT).
A dilute mineral acid such as dilute HCl is used. It converts the amine into a water-soluble ammonium chloride salt.
A strong base like NaOH is added to the aqueous salt layer. It regenerates the neutral parent amine, which can then be separated.
Amine salts are ionic. Ether is a non-polar organic solvent, so it cannot dissolve ionic salts well. That is why the salt stays in water and the neutral non-basic compound stays in ether.
Yes. It links directly to the basic character of amines, salt formation with acids, and regeneration with NaOH, which are common one-liner and reasoning-based NEET points.
