To calculate the corrosion current density i_corr of Zinc in the galvanic couple with Copper, we can use the Stern-Geary equation:i_corr = B / R_pwhere B is the Stern-Geary constant and R_p is the polarization resistance.The Stern-Geary constant B can be calculated using the Tafel slopes b_a and b_c for the anodic and cathodic reactions:B = b_a * b_c / 2.3 * b_a + b_c For Zinc, the Tafel slopes are approximately b_a = 120 mV/decade and b_c = -120 mV/decade.Now, we can calculate the Stern-Geary constant B :B = 120 * 120 / 2.3 * 120 + 120 B = 14400 / 2.3 * 240 B = 14400 / 552B 26.1 mVNow that we have the Stern-Geary constant B , we can calculate the corrosion current density i_corr using the polarization resistance R_p given as 625 :i_corr = B / R_pi_corr = 26.1 mV / 625 To convert mV to V, divide by 1000:i_corr = 0.0261 V / 625 i_corr 4.176 10^-5 A/cmSo, the corrosion current density of Zinc in the galvanic couple with Copper in a 0.1 M KCl electrolyte solution at 25 C is approximately 4.176 10^-5 A/cm.