Question

For the following reactions, equilibrium constants are given : $S\left(s\right)+O_{2}\left(g\right)$ ${\rightleftharpoons}$ $SO_{2}\left(g\right); K_{1} =10^{52}$ $2S\left(s\right)+3O_{2}\left(g\right)$ ${\rightleftharpoons}$ $2SO_{3}\left(g\right); K_{2} = 10^{129}$ The eqilibrium constant for the reaction, $2SO_{2}\left(g\right)+O_{2}\left(g\right)$ ${\rightleftharpoons}$ $2SO_{3}\left(g\right)$ is :

• A. 10$^{181}$
• B. 10$^{154}$
• C. 10$^{25}$
• D. 10$^{77}$

Answer 1

Answer: (C)

10$^{25}$

Answer 2

$2SO_{2 }\left(g\right) + O_{2} \left(g\right)\to2SO_{3} \left(g\right)$
$K_{eq} = \frac{\left[SO_{3}\right]^{2}}{\left[O_{2}\right]\left[SO_{2}\right]^{2}}$
$= \frac{K_{2}}{K_{1}} = \frac{10^{129}}{10^{104}} = 10^{25}$