Draw the polarization diagram for an electrode reaction which shows only charge-transfer polarization and for which the exchange current density is 10-5 Acm-2 , the transfer coefficient =0.45 and n=2. Use Excel or equivalent to plot E as function of log ia, log ic, and log i in the range from -0.8 V to +0.2V. Assume Eeq = -0.3 V (all vs SHE).

1. Draw the polarization diagram for an electrode reaction which shows only charge-transfer polarization and for which the exchange current density is 10-5 Acm2, the transfer coefficient a=0.45 and n=2. Use Excel or equivalent to plot E as function of log ia, logic, and log i in the range from -0.8 V to +0.2V. Assume Eeq = -0.3 V (all vs SHE). 2. Calculate the overvoltage n in volt for an electrode reaction showing only charge-transfer polarization with an exchange current density io=5x10-7 Acm?, a=0.5 and 1 electron taking part in the rate determining charge transfer reaction, at a net current density of 10mA/cm? 3. Calculate the limiting current density for the reaction O2 + 2H20 + 4e +40H in still, naturally aerated water at room temperature. Assume for those conditions the following values: Concentration of Oz in water C=8ppm Diffusion distance x=0.1mm Oxygen diffusivity D=1x105cm/s