1. The potential of an iron electrode when polarized as cathode at 0.001 A/cm? is -0.916...

  

Transcribed Image Text:

1. The potential of an iron electrode when polarized as cathode at 0.001 A/cm? is -0.916 V versus 1N calomel half-cell. The pH of the electrolyte is 4.0. What is the value of the hydrogen overvoltage? Ans.: -0.40 V. Notes: Assume p = 1atm, T = 298°K. Assume that there is no Fe" in the electrolyte; therefore, when Fe is cathodically polarized, Fe" will not plate out. The only cathodic reaction that can occur, therefore, is hydrogen evolution. Hints: 1 (over potential) = (actual) - . The cathode potential, o (actual), is in volts vs the 1N calomel reference electrode. When you calculate , P it will be in volts vs the standard hydrogen electrode. To get the over potential, n; the potentials o (actual) and must be taken with respect to the same reference electrode. Ans for $HtH, = -0.236 VSHE Don't forget to calculate the hydrogen overvoltage (also called the over potential). %3D 1. The potential of an iron electrode when polarized as cathode at 0.001 A/cm? is -0.916 V versus 1N calomel half-cell. The pH of the electrolyte is 4.0. What is the value of the hydrogen overvoltage? Ans.: -0.40 V. Notes: Assume p = 1atm, T = 298°K. Assume that there is no Fe" in the electrolyte; therefore, when Fe is cathodically polarized, Fe" will not plate out. The only cathodic reaction that can occur, therefore, is hydrogen evolution. Hints: 1 (over potential) = (actual) - . The cathode potential, o (actual), is in volts vs the 1N calomel reference electrode. When you calculate , P it will be in volts vs the standard hydrogen electrode. To get the over potential, n; the potentials o (actual) and must be taken with respect to the same reference electrode. Ans for $HtH, = -0.236 VSHE Don't forget to calculate the hydrogen overvoltage (also called the over potential). %3D

Answer rating: 100% (QA)

Hydrogen overvoltage by Tafel equation E0ablog I E0Overpotent... View the full answer