Question

$8$g of divalent metal produces $9.8$g of its nitride. The approx atomic weight of metal is:

• A. $9.8$
• B. $42$
• C. $35$
• D. $8$

Answer 1

The correct option is B $42$

Let the metal be $M$ with atomic weight be $x$.

So $3M+N_2⟶M_3{N}_2$

$3x$ $3x+28$

So, $\frac{8}{3x}=\frac{9.8}{3x+28}$

Which on solving for $x$ gives $42$

The metal is calcium.