Question

What is the corrosion rate of iron in a 0.1 M HCl solution at 298 K, given that the corrosion potential is -0.44 V and the current density is 1.2 mA/cm²?

Answer 1

To calculate the corrosion rate of iron in a 0.1 M HCl solution, we can use Faraday's law of electrolysis. The formula for Faraday's law is:Corrosion rate =  i * M * n  /  F *  * A where:i = current density  1.2 mA/cm M = molar mass of iron  55.85 g/mol n = number of electrons involved in the redox reaction  2 for iron, as Fe  Fe + 2e F = Faraday's constant  96,485 C/mol  = density of iron  7.87 g/cm A = area of the iron surface  1 cm First, we need to convert the current density from mA/cm to A/cm:1.2 mA/cm = 0.0012 A/cmNow, we can plug the values into the formula:Corrosion rate =  0.0012 A/cm * 55.85 g/mol * 2  /  96,485 C/mol * 7.87 g/cm * 1 cm Corrosion rate =  0.1338 gmolC  /  759,076.95 gmolCcm Corrosion rate = 1.762  10 cm/yearThe corrosion rate of iron in a 0.1 M HCl solution at 298 K is approximately 1.762  10 cm/year.