7. (10%) (a) Determine the oxidation number of nitrogen in the following chemicals: N2; NO3-; NO2-; NH3.
(b) Based on the changes in the oxidation number, determine whether the nitrification, denitrification, and fixation reactions are reduction or oxidation reactions.
7. (10%) (a) Determine the oxidation number of nitrogen in the following chemicals: N2; NO3-; NO2-;...