STD 11 - 2. structure of atom — JEE STD 11 Science — Question

$C{H_3} - \begin{array}{*{20}{c}}
  {\begin{array}{*{20}{c}}
  {C{H_3}} \\ 
  | 
\end{array}} \\ 
  C \\ 
  | \\ 
  {C{H_3}} 
\end{array} - C{H_2} - Cl$

$A+B\xrightarrow{K}C$:

(Image)

Pre-exponential factors for the forward and backward reactions are $10^{15} \mathrm{~s}^{-1}$ and $10^{11} \mathrm{~s}^{-1}$, respectively. If the value of $\log \mathrm{K}$ for the reaction at $500 \mathrm{~K}$ is $6$ , the value of $\left|\log \mathrm{k}_{\mathrm{b}}\right|$ at $250 \mathrm{~K}$ is $\qquad$

$[\mathrm{K}=$ equilibrium constant of the reaction

$\mathrm{k}_{\mathrm{f}}=$ rate constant of forward reaction

$\mathrm{k}_{\mathrm{b}}=$ rate constant of backward reaction]