To calculate the equilibrium constant Kc for the given reaction at 25C, we can use the expression:Kc = [CH4][H2O] / [CO][H2]^3 Given the equilibrium concentrations:[CO] = 0.10 M[H2] = 0.20 M[CH4] = 0.015 M[H2O] = 0.035 MNow, we can plug these values into the Kc expression:Kc = 0.015 0.035 / 0.10 0.20 ^3 Kc = 0.015 0.035 / 0.10 0.008 Kc = 0.000525 / 0.0008Kc 0.656Therefore, the equilibrium constant Kc for the given reaction at 25C is approximately 0.656.