Consider the following electrode process of a cell,
$ {Cl^{-1} -> \frac{1}{2} Cl_2 + e^{-}}$
$ {[MCl + e^{-} -> M + Cl^{-} ] }$
If EMF of this cell is $-1.140\, V$ and $E^0$ value of the cell is $-0.55\,V$ at $298\,K$, the value of the equilibrium constant of the sparingly soluble salt MCl is in the order of