Question

A compound with molar mass 180 is acylated with $C{H}_{3}COCl$ to get a compound with molar mass 390. The numbeof amino groups present per molecules of the former compounds is:

Answer 1

The acylation of an amine group can be represented as

$RN{H}_2+C{H}_{3}COCl\to RNHCOC{H}_3+HCl$

Molecular mass of the compound $=180$

Molecular mass of the product $=390$

Increase in molecular mass of the product $=390-180=210$

Since in acylation, one $H$ group per $N{H}_2$ is replaced by one $COC{H}_3$ group, hence

Mass of $COC{H}_3=43$

Mass of $H=1$

Mass added per $N{H}_2$ group$=42$

Hence number of amino groups$=\frac{210}{42}=5$