A magnesium bar with a mass of 7.8 kg is attached to a buried iron pipe to serve as a sacrificial anode. An average current of 0.026 A flows between the bar and the pipe. a. What half-reaction takes place at the surface of the magnesium bar? (Use the lowest possible coefficients. Be sure to specify states such as (aq) or (s). If a box is not needed, leave it blank.) b. What half-reaction takes place at the surface of the iron pipe? There is some oxygen around the iron pipe. (Use the lowest possible coefficients. Be sure to specify states such as (aq) or (s). If a box is not needed, leave it blank.) C. In which direction do electrons flow between the two surfaces? from the iron pipe to the magnesium bar from the magnesium bar to the iron pipe d. How many years would it take for the entire magnesium bar to be consumed? years