To calculate the equilibrium constant Kc, we need to know the concentrations of all species involved in the reaction at equilibrium. However, the concentration of H2O is not provided. We can use the initial concentrations and the stoichiometry of the reaction to determine the change in concentrations and find the equilibrium concentration of H2O.Let's denote the change in concentration of CO2 and H2 as x. Since the stoichiometry of the reaction is 1:1:1:1, the change in concentration of CO and H2O will also be x.At equilibrium, the concentrations will be:CO2: 1.2 - xH2: 0.8 - xCO: 0.6 + xH2O: xNow we can write the expression for Kc:Kc = [CO][H2O] / [CO2][H2] We need to find the value of x to determine the equilibrium concentrations and calculate Kc. However, without any additional information, such as the value of Kc or any equilibrium concentrations, we cannot solve for x and determine the equilibrium constant Kc for this reaction at 25C.