Question

Schiff’s base is prepared from:
(A) Carbonyl compound and primary amine
(B) Carbonyl compound and secondary amine
(C) Carbonyl compound and tertiary amine
(D) All of these

Answer 1

Hint:To solve this we must know the Schiff’s base. Schiff’s base is a condensation product of amine with a carbonyl compound. The Schiff’s base contains imine or azomethine $\left( { - {\text{C}} = {\text{N}} - } \right)$ functional group. Schiff’s base reaction is a specific reaction for an aldehyde group.

Complete step-by-step solution:We know that Schiff’s base is a condensation product of amine with a carbonyl compound. The Schiff’s base contains imine or azomethine $\left( { - {\text{C}} = {\text{N}} - } \right)$ functional group. Schiff’s base reaction is a specific reaction for an aldehyde group.
Schiff’s base is generally an aldehyde or ketone complex in which the carbonyl group of aldehyde or ketone is substituted by an imine or azomethine group. The general structure of a Schiff’s base is as follows:
${{\text{R}}_2}{\text{C}} = {\text{NR'}}$
Schiff’s base is a subclass of imines. It is a subordinate of aldehyde or secondary keto-amines depending on the structure.
Schiff’s base is prepared by the condensation of primary amine with an aldehyde which is a carbonyl compound. Organic solvents like methanol, tetrahydrofuran and 1,2-dichloroethane are used in preparation of Schiff’s base.
Natural ${\text{\alpha }}$-amino acids like glycine, l-alanine, l-leucine are condensed with aromatic aldehydes like methylbenzaldehyde or p-ethylbenzaldehyde to produce Schiff’s base.
Thus, Schiff’s base is prepared from carbonyl compounds and primary amine.

Thus, the correct option is (A) carbonyl compound and primary amine.

Note:Schiff’s base is used as a reagent to detect the presence of an aldehyde or a ketone. Schiff’s base contains fuchsin dye which is decolourised by sulphuric acid. Immediate appearance of red or pink colour confirms the presence of aliphatic aldehydes or ketones and if the red or pink colour appears slowly then aromatic aldehydes or ketones are present.