To calculate the corrosion potential for an iron electrode in a galvanic couple with a standard hydrogen electrode, we need to use the Nernst equation. The Nernst equation is given by:E = E - RT/nF * ln Q where E is the electrode potential, E is the standard electrode potential, R is the gas constant 8.314 J/molK , T is the temperature in Kelvin 25C = 298.15 K , n is the number of electrons transferred in the redox reaction, F is the Faraday constant 96,485 C/mol , and Q is the reaction quotient.For the iron electrode, the half-reaction is:Fe + 2e Fe s The standard electrode potential E for this reaction is -0.44 V. The number of electrons transferred n is 2.The reaction quotient Q can be calculated using the concentrations of the species involved in the reaction. In this case, the concentration of Fe is given as 0.05 M, and the concentration of Fe s is 1 since it is a pure solid . The pH is given as 7, which means the hydrogen ion concentration [H] is 10^-7 M.Q = [Fe]/[Fe s ] = 0.05/1 = 0.05Now we can plug these values into the Nernst equation:E = -0.44 - 8.314 * 298.15 / 2 * 96485 * ln 0.05 E = -0.44 - 0.043 / 2 * ln 0.05 E = -0.44 + 0.0215 * 2.9957E = -0.44 + 0.0644E = -0.3756 VThe corrosion potential for the iron electrode in a galvanic couple with a standard hydrogen electrode at 25C, with a concentration of Fe ion of 0.05 M and pH of 7, is approximately -0.376 V.