To calculate the corrosion rate of the steel rod in mmpy, we need to follow these steps:1. Calculate the weight loss per year.2. Convert the weight loss per year to the equivalent number of moles of iron lost per year.3. Use Faraday's law of electrolysis to determine the corrosion current.4. Calculate the corrosion rate in mmpy.Step 1: Calculate the weight loss per yearWeight loss in 24 hours = 0.48 gWeight loss per hour = 0.48 g / 24 hours = 0.02 g/hourWeight loss per year = 0.02 g/hour * 24 hours/day * 365 days/year = 175.2 g/yearStep 2: Convert the weight loss per year to the equivalent number of moles of iron lost per yearThe molar mass of iron Fe is 55.85 g/mol.Moles of iron lost per year = 175.2 g/year / 55.85 g/mol = 3.136 mol/yearStep 3: Use Faraday's law of electrolysis to determine the corrosion currentFaraday's constant F = 96485 C/mol Coulombs per mole of electrons The balanced half-reaction for the corrosion of iron is: Fe Fe + 2eThus, 2 moles of electrons are transferred per mole of iron corroded.Moles of electrons transferred per year = 3.136 mol/year * 2 = 6.272 mol/yearTotal charge transferred per year = 6.272 mol/year * 96485 C/mol = 605,372,920 C/yearStep 4: Calculate the corrosion rate in mmpyThe corrosion current density i_corr can be calculated as follows:i_corr = Total charge transferred per year / Area of steel rod * Time in seconds per year i_corr = 605,372,920 C/year / 3.14 cm * 31,536,000 s/year = 6.11 x 10 A/cmThe corrosion rate CR in mmpy can be calculated using the following formula:CR = i_corr * K * 10 / n * F * Where:K = 3.27 x 10 constant for converting A/cm to mmpy n = 2 number of electrons transferred per mole of iron corroded F = 96485 C/mol Faraday's constant = 7.87 g/cm density of iron CR = 6.11 x 10 * 3.27 x 10 * 10 / 2 * 96485 * 7.87 = 0.000162 mmpyThe corrosion rate of the steel rod in a galvanic coupling with a copper strip at 25C is approximately 0.000162 mmpy.