Question

The equivalent weight of a certain trivalent element is 20. Molecular weight of its oxide is :

• A. 152
• B. 56
• C. 168
• D. 68

Answer 1

The correct option is C 168

$\text{Atomic mass of element}=\text{Equivalent mass of element}\times \text{Valency}=20\times 3=60g/mol$ \

The oxide can be represented as $E_2{O}_3$ where E represents element.

The molecular weight of oxide is $2\left(60\right)+3\left(16\right)=168g/mol$

Hence the correct option is C.