A mixture of an amine and a non-basic organic compound, both insoluble in water, is dissolved in ether and shaken with dilute hydrochloric acid. Which of the following takes place?
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → The amine forms a salt that passes into the water layer, while the non-basic compound stays in the ether layer.
Amines are basic, so they react with hydrochloric acid to form ammonium salts. These salts are ionic: they are soluble in water but insoluble in ether.
\( \displaystyle \ce{RNH2 + HCl -> RNH3^+Cl^-} \)
The non-basic compound does not react with the acid and stays in the ether layer.
After the two layers are separated, the amine is got back from the water layer by adding a base such as NaOH:
\( \displaystyle \ce{RNH3^+Cl^- + NaOH -> RNH2 + H2O + NaCl} \)
Option (1) The amine stays in the ether layer and the non-basic compound passes into the water layer. — Incorrect. The amine does not stay in ether, because it turns into a water soluble salt; the non-basic compound is insoluble in water and does not react.
Option (2) The amine forms a salt that stays dissolved in the ether layer. — Incorrect. Amine salts are insoluble in organic solvents like ether.
Option (4) Both compounds form salts and pass into the water layer. — Incorrect. A non-basic compound cannot form a salt with an acid, so it does not pass into the water layer.
NCERT (2026-27 edition):
9.6 Chemical Reactions – “Amine salts on treatment with a base like NaOH, regenerate the parent amine.”
“Amine salts are soluble in water but insoluble in organic solvents like ether. This reaction is the basis for the separation of amines from the non basic organic compounds insoluble in water.”