1. The three -electron reduction of the oxygen molecule leads to the formation of: hydroxyl radical - HO hydrogen peroxide - H_(2)O_(2) hydroxyl I anion -HO^- superoxide anion radical water

The correct answer is: superoxide anion radical.<br /><br />The three-electron reduction of the oxygen molecule (O2) leads to the formation of the superoxide anion radical (O2-). This process involves the addition of one electron to each of the two oxygen atoms in the O2 molecule, resulting in the formation of the superoxide anion radical. This radical is a reactive species that plays a crucial role in various biological and chemical processes.