If a reaction is reversed, the equilibrium constant (Kc) for the reversed reaction becomes the reciprocal of the original equilibrium constant. For a reaction:
A + B ⇌ C + DThe equilibrium constant Kc = [C][D]/[A][B]For the reversed reaction:C + D ⇌ A + BThe equilibrium constant Kc(reversed) = [A][B]/[C][D]Thus, Kc(reversed) = 1/Kc.