Question

What is the equivalent mass of $A{l}_2{O}_3$ in the following reaction?

$4Al+3O_2\stackrel{\Delta }{\to }2A{l}_2{O}_3$

• A. 34
• B. 17
• C. 68
• D. 51

Answer 1

The correct option is B 17

$4Al+3O_2⟶2A{l}_2{O}_3$

$108$ $g$ $96$ $g$ $204$ $g$

We can say $204$ $g$ $A{l}_2{O}_3$ displaces $96$ $g$ oxygen.

According to the definition of equivalent mass it the amount of substance that displaces $8$ $g$ $O_2$.

$\therefore 204$ $g$ $A{l}_2{O}_3⟶96$ $g$ $O_2$

$x$ $gA{l}_2{O}_3⟶8$ $g$ $O_2$

$x=\frac{8\times 204}{96}=17$ $g$

Hence, option $B$ is correct.