$\begin{array}{l} \log {k_c} = \frac{{ - 196860}}{{ - 2.303x8.314x298}}\\ {\rm{Calcualte it we get }}\\ {\rm{log }}{{\rm{k}}_c}{\rm{ = 34}}{\rm{.5014}}\\ {\rm{Take antilog both side we get }}\\ {{\rm{k}}_{\rm{c}}} = 3.192x{10^{34}} \end{array}$