Classify these half-reactions by typing in “O” for “oxidation half-reaction,” “R” for “reduction half- reaction,” and “N” for “neither.” Upper H upper C l right arrow upper m g upper C l subscript 2. Upper m g right arrow upper M g upper C l subscript 2 plus 2 e superscript minus. 2 upper H upper C l plus 2 e superscript minus right arrow upper H subscript 2.