Question

$9$ g of trivalent metal combines with $8$ g of oxygen. The atomic mass of the metal is:

• A. $9$
• B. $18$
• C. $27$
• D. $36$

Answer 1

The correct option is C $27$

Equivalent mass of metal$=\frac{\text{weight of the metal}}{\text{weight of oxygen}}\times 8$

$=\frac{9}{8}\times 8$

$=9$

Since the metal is trivalent.

Atomic mass $=$ Equivalent mass$\times 3$

$=9\times 3=27$.