A compound with molecular mass 180 is acylated with CH3COCl to get a compound with molecular mass 390. The number of amino groups present per molecule of the former compound is :
6
2
5
4
Since,each-COCH3 group displaces one H atom in the reaction of one mole of the group, the molecular mass increases with 42 units.
Since, the mass increases by (390-180)=210, hence the number of NH2 the group is 210/42 = 5.