Question

$A{B}_3\left(g\right)$ is dissociated as $A{B}_3\left(g\right)\rightleftharpoons A{B}_2\left(g\right)+\frac{1}{2}{B}_2\left(g\right)$.
When the initial pressure of $A{B}_2$ is 800 torr and the total pressure developed at equlibrium is $900torr$. What fraction of $A{B}_3\left(g\right)$ is dissociated?

• A. 10%
• B. 20%
• C. 25%
• D. 30%

Answer 1

The correct option is C 25%

$A{B}_3\left(g\right)\rightleftharpoons A{B}_2\left(g\right)+\frac{1}{2}{B}_2\left(g\right)$
At eq. $800-x$ $x$ $\frac{x}{2}$
$800-x+x+\frac{x}{2}=900\Rightarrow x=200$
% dissociated =$\frac{200}{800}\times 100=25\%$