To calculate the rate of the electrochemical reaction, we first need to determine the number of moles of copper formed at the cathode. 1. Calculate the moles of copper formed:moles of copper = mass of copper / atomic weight of coppermoles of copper = 4 g / 63.5 g/molmoles of copper = 0.0631 mol2. Calculate the total charge passed through the solution:Current I = 2.5 ATime t = 2 hours = 2 * 60 * 60 seconds = 7200 secondsTotal charge Q = Current I x Time t Q = 2.5 A * 7200 sQ = 18000 Coulombs3. Calculate the number of Faradays F passed through the solution:1 Faraday F = 96485 Coulombs/molNumber of Faradays = Total charge Q / Faraday constantNumber of Faradays = 18000 C / 96485 C/molNumber of Faradays = 0.1865 mol4. Calculate the number of electrons n involved in the reaction:Copper ions Cu gain 2 electrons to form copper atoms Cu .Cu + 2e CuSo, n = 2.5. Calculate the rate of the electrochemical reaction:Rate of reaction = moles of copper / number of Faradays * number of electrons Rate of reaction = 0.0631 mol / 0.1865 mol * 2 Rate of reaction = 0.0631 mol / 0.373 molRate of reaction = 0.169The rate of the electrochemical reaction is 0.169 mol of copper per mole of electrons passed through the solution.