Question

The equilibrium constant for the reaction is $K_c=4.9\times {10}^{-2}$.

${SO}_3\left(g\right)\rightleftharpoons {SO}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)$

The value of $K_c$ for the reaction:

$2{SO}_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2{SO}_3\left(g\right)$ will be:

• A. $416$
• B. $2.40\times {10}^{-3}$
• C. $9.8\times {10}^{-2}$
• D. $4.9\times {10}^{-2}$

Answer 1

The correct option is A $416$

Equilibrium constant for the reaction:
${SO}_3\left(g\right)\rightleftharpoons {SO}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)$
$K_c=4.9\times {10}^{-2}$

${SO}_2\left(g\right)+\frac{1}{2}{O}_2\left(g\right)\rightleftharpoons {SO}_3\left(g\right)$

$K_c=\frac{1}{4.9\times {10}^{-2}}$

Also, $2{SO}_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2{SO}_3\left(g\right)$
$K_c={\left(\frac{1}{4.9\times {10}^{-2}}\right)}^2=\frac{{10}^4}{{\left(4.9\right)}^2}=416.49\simeq 416$

Hence, option A is correct.