To calculate the standard free energy change G for the redox reaction, we first need to determine the standard cell potential Ecell for the reaction. The cell potential can be found using the Nernst equation:Ecell = Ered cathode - Ered anode In this reaction, Mg is being oxidized losing electrons and H+ is being reduced gaining electrons . Therefore, Mg is the anode and H+ is the cathode. We are given the standard reduction potentials for both half-reactions:Ered Mg2+/Mg = -2.37 V anode Ered H+/H2 = 0 V cathode Now we can calculate the standard cell potential:Ecell = 0 V - -2.37 V = 2.37 VNext, we can use the relationship between the standard cell potential and the standard free energy change:G = -nFEcellwhere n is the number of moles of electrons transferred in the reaction in this case, 2 moles and F is the Faraday constant 96,485 C/mol .G = - 2 mol 96,485 C/mol 2.37 V = -457,331.9 J/molSince the standard free energy change is typically expressed in kJ/mol, we can convert the value:G = -457.33 kJ/molSo, the standard free energy change for the given redox reaction at 298 K is -457.33 kJ/mol.