Question

A compound with molecular mass $180$ is acylated with $CH_3COCl$ to get a compound with molecular mass $390$. The number of amino groups present per molecule of the former compound is

• A. 2
• B. 5
• C. 4
• D. 6

Answer 1

Answer: (B)

5

Answer 2

Since each - $COCH_3$ group displace one H atom in the reaction molecular mass increases with 42 unit.
Since the mass increases by (390 - 180) = 210, hence the number of - $NH_2$ group is $=\frac{210}{42}=5$.