Question

One mole of $S{O}_3$ was placed in a litre reaction flask at a given temperature when the reaction equilibrium was established in the reaction.
$2S{O}_3\rightleftharpoons 2S{O}_2+O_2$ the vessel was found to contain $0.6$ mol of $S{O}_2$. The value of the equilibrium constant is :

• A. $0.36$
• B. $0.675$
• C. $0.45$
• D. $0.54$

Answer 1

The correct option is B $0.675$

$\underset{\underset{1-2x}{1}}{2S{O}_3}\rightleftharpoons \underset{\underset{2x}{0}}{2S{O}_2}+\underset{\underset{x}{0}}{O_2}$
$\therefore 2x=0.6,\therefore x=0.3$
$\left[S{O}_3\right]=1-2x=1-0.6=0.4$
$\left[S{O}_2\right]=2x=0.6$
$\left[O_2\right]=x=0.3$
$K=\frac{x\times (2x{)}^2}{(1-2xx{)}^2}=\frac{0.3\times 0.6\times 0.6}{0.4\times 0.4}=0.675$