c
\(\quad \quad \quad O_{2}\;\;+\;\;2 S O_{2} \leftrightarrow 2 S O_{3}\)

\(a t\; t=0 \;\;1 \quad \;\;\;\;\;2\quad \;\;\;\;\;\;\quad 0\)

\(at \;equil.(1-\alpha) \; 2(1-\alpha)\;2\alpha\)

\(Given\,at\,equilibrium\)

\({K_C} = \frac{{{{(2\alpha )}^2}}}{{(1 - \alpha ){{(2 - 2\alpha )}^2}}} = \mathop {\mathop {\frac{{{{(0.8)}^2}}}{{(1 - 0.8){{(1 - 0.8)}^2}}}}\limits^{\alpha  = 0.8} }\limits^{2\alpha  = 1.6} \)

\( = \frac{{0.64}}{{0.002}}\)

\({K_C} = 80\)