Which half-reaction has the highest standard electrode potential?

The half-reaction with the highest standard electrode potential is associated with the process that most readily accepts electrons. The standard electrode potential indicates how likely a species is to gain electrons and be reduced. A more positive potential corresponds to a greater tendency for reduction, making the species a stronger oxidizing agent.

In the case of the half-reaction involving bromine, where Br2 is reduced to Br−, this reaction has a high standard electrode potential. The ability of Br2 to accept electrons and convert to bromide ions indicates its strong oxidizing capability. In standardized tables, this specific half-reaction has one of the higher electrode potentials among common redox couples.

The other half-reactions, while also capable of reduction, exhibit lower standard electrode potentials compared to the bromine half-reaction. Therefore, Br2's strong tendency to accept electrons substantiates its classification as having the highest standard electrode potential among the listed choices. This characteristic is essential for electrochemical applications where oxidizing agents need to be identified for specific reactions.