Answer: Option (4) is the correct answer.
Explanation:
Half reactions are the reactions that represent oxidation and reduction reactions through separate steps.
For example, [tex]2Na + Br_{2} \rightarrow 2Na^{+} + 2Br^{-}[/tex] the oxidation and reduction half-reaction will be as follows.
Oxidation half-reaction: [tex]2Na \rightarrow Na^{+} + 2e^{-}[/tex]
Reduction half-reaction: [tex]Br_{2} + 2e^{-} \rightarrow 2Br^{-}[/tex]
Thus, we can conclude that half-reactions can be written to represent all oxidation and reduction reactions.
