To calculate the corrosion current density using Tafel extrapolation, we need to know the Tafel slopes for both the anodic and cathodic reactions, as well as the exchange current density. However, these values are not provided in the problem statement. Assuming you have these values, you can follow these steps to calculate the corrosion current density:1. Write down the Tafel equations for both the anodic and cathodic reactions:Anodic reaction: E = E0 - Ba * log10 ia / i0 Cathodic reaction: E = E0 + Bc * log10 ic / i0 where E is the electrode potential, E0 is the standard potential, Ba and Bc are the Tafel slopes for the anodic and cathodic reactions, respectively, ia and ic are the anodic and cathodic current densities, respectively, and i0 is the exchange current density.2. Set the anodic and cathodic Tafel equations equal to each other and solve for the corrosion current density icorr :E0 - Ba * log10 ia / i0 = E0 + Bc * log10 ic / i0 3. Rearrange the equation to solve for icorr:icorr = i0 * 10^ Ba * log10 ia / i0 - Bc * log10 ic / i0 / Ba + Bc 4. Plug in the given values and the Tafel slopes and exchange current density if provided into the equation to calculate the corrosion current density.5. Finally, divide the corrosion current density by the electrode area 5 cm to obtain the corrosion current density per unit area.Please note that without the Tafel slopes and exchange current density values, it is not possible to provide a numerical answer to this problem.