To calculate the corrosion current density i_corr of the steel pipe, we need to use the Stern-Geary equation:i_corr = a * c * i0 / 2.303 * a + c * E_corr - E_eq where:- a and c are the anodic and cathodic Tafel slopes, respectively in mV/dec - i0 is the exchange current density in A/m - E_corr is the corrosion potential in V - E_eq is the equilibrium potential in V Since we are given the Tafel slope 120 mV/dec , we can assume that the anodic and cathodic Tafel slopes are equal a = c = 120 mV/dec . However, we do not have enough information to determine the exchange current density i0 and the equilibrium potential E_eq .To find these values, we would need more information about the specific steel material and the saltwater environment. This information could be obtained from experimental data or literature sources. Once we have these values, we can plug them into the Stern-Geary equation to calculate the corrosion current density.