To calculate the standard free energy change G for the redox reaction, we need to use the Nernst equation:G = -nFEwhere n is the number of moles of electrons transferred, F is the Faraday constant 96,485 C/mol , and E is the standard cell potential.First, we need to determine the half-reactions for the redox reaction:Oxidation half-reaction H is oxidized to H :H g 2 H aq + 2 eSince there are 3 moles of H, multiply the half-reaction by 3:3 H g 6 H aq + 6 eReduction half-reaction Fe is reduced to Fe :Fe aq + 3 e Fe s Since there are 2 moles of Fe, multiply the half-reaction by 2:2 Fe aq + 6 e 2 Fe s Now, we need to find the standard reduction potentials E for each half-reaction. These values can be found in a standard reduction potential table:E H/H = 0.00 V by definition E Fe/Fe = -0.036 VNext, we need to calculate the standard cell potential E for the overall redox reaction:E cell = E cathode - E anode E cell = E Fe/Fe - E H/H E cell = -0.036 V - 0.00 VE cell = -0.036 VNow, we can calculate the standard free energy change G using the Nernst equation:G = -nFEG = -6 mol e * 96,485 C/mol e * -0.036 V G = 20,923.56 J/molSince the standard free energy change is usually expressed in kJ/mol, we can convert the value:G = 20.92 kJ/mol