Question

A metal nitride $M_3{N}_2$ contains 28% of nitrogen.The atomic mass of metal M is

• A. 24
• B. 54
• C. 9
• D. 87.62

Answer 1

Answer: (A)

Moles of $N=\frac{28}{14}=2$
Moles of metal, $M=\frac{100-28}{a}=\frac{72}{a}$
Mole ratio, $M:N=\frac{72}{a}:2=3:2$
$\frac{72}{a}=3$
$a=\frac{72}{a}=24$