Question

A compound contains 28% of nitrogen and 72% metal by mass. 3 atoms of the metal combine with 2 atoms of the nitrogen. Find the atomic mass of the metal.

• A. 24
• B. 25
• C. 23
• D. 21

Answer 1

The correct option is A 24

Three atoms of M combine with 2 atoms of N.

Equivalent weight of $N=\frac{14}{3}$ (valency of N in compound = 3)

28g N combines with 72g metal.

$\frac{14}{3}$ N combines $=\frac{72}{28}\times \frac{14}{3}=12$

The equivalent weight of metal =12

Atomic mass of metal = equivalent weight $\times$ valency$=12\times 2=24$.

Hence, option $A$ is correct.