The reaction described involves warming an organic compound with chloroform (
CHCl3) and an alcoholic solution of potassium hydroxide
(KOH). This procedure is part of the isocyanide test or carbylamine reaction. The carbylamine reaction is used to detect the presence of primary amines, particularly aromatic primary amines. The test gives a positive result when a foul-smelling substance, isocyanide (also known as isonitrile), is formed.
In this reaction, the primary amine reacts with chloroform and base to form an isocyanide. The general reaction can be represented as follows:
R−NH2+CHCl3+3‌KOH⟶R−NC+3‌KCl+3H2O
Where
R−NH2 represents a primary amine.
Looking at the provided options:
Option A: N - Methyl-o-Methylaniline - This compound is a secondary amine (since the nitrogen atom is bonded to two carbon atoms), so it will not give a positive result. Option B: N,N-Dimethylaniline - This compound is a tertiary amine (since the nitrogen atom is bonded to three carbon atoms), so it will not give a positive result.
Option C: p-Methylbenzylamine - This compound can be considered under the primary amine category if examined closely (benzylamine part) and should be able to give a positive carbylamine test.
Option D: N-Methyl-p-Methylaniline - This compound is also a secondary amine (since the nitrogen atom is bonded to two carbon atoms), so it will not give a positive result.
Thus, the correct answer is: Option C: p-Methylbenzylamine. This compound is a primary amine and will give a positive result in the carbylamine reaction by forming an isocyanide.