A steel pipe with an outer diameter of 10 cm and a wall thickness of 5 mm is used to transport a corrosive liquid. The liquid has a pH of 2 and a chloride ion concentration of 1000 ppm. The pipe material has a corrosion rate of 0.5 mm per year under these conditions. a) Calculate the time required for the pipe wall to corrode completely. b) If a corrosion allowance of 3 mm is added to the pipe wall thickness, what is the expected service life of the pipe? c) If the pH of the liquid is increased to 4, how does it affect the corrosion rate and the expected service life of the pipe? Assume all other conditions remain the same.