Question

Acid anhydride on reaction with primary amines gives:
$A.amide$
$B.imide$
$C.secondary amine$
$D.imine$

Answer 1

This reaction is termed as acylation of amines. Acid anhydride undergoes nucleophilic substitution reaction in which the H atom in the amino group is replaced by acyl group. They are highly reactive toward nucleophiles.

Complete step by step answer:
We know that nucleophiles are a substance that donates electron pairs to electron deficient species. They are negatively charged and are neutral. Reaction in which a leaving group is replaced by a nucleophile is called Nuclear substitution reaction.
As we know, acid anhydride are the molecules that are capable of forming acidic solutions in water. One common example for acid anhydride is Ethanoic anhydride. They are less reactive compared to acid chloride. Acid anhydride can be prepared from hydrocarbon, ethane.
Let us see an example for acid anhydride,
Carboxylic anhydride is a common organic acid anhydride.
The next thing to remember is the ‘Amines’. Amines are organic compounds derived from ammonia. They are obtained by replacing its one or more hydrogen atom by alkyl or aryl group. If one hydrogen atom of $N{H_3}$ is replaced by an alkyl or aryl group, primary amine is formed. The term primary is denoted by the symbol ${1^ \circ }$.
Let us see an example for ${1^ \circ }$ amine,
Methyl amine $\left( {C{H_3}N{H_2}} \right)$
When acid anhydride reacts with primary amine, amide is formed. This reaction is called acylation of amines and it follows nucleophilic substitution reactions.

Therefore, the correct answer is option A.

Note:
Amide groups have the general chemical formula $CO - NH$. They may also be prepared by the polymerization of amino acids or its derivatives. Amides are used to synthesize substances like nylon and Kevlar.