Answer:
To determine the change in oxidation state of the reducing agent in the reaction \( \text{Cl}_2 + 2\text{Br}^- \rightarrow 2\text{Cl}^- + \text{Br}_2 \), we need to identify the reducing agent, which is the species that undergoes oxidation.
In this reaction, chlorine (Cl) is reduced from an oxidation state of 0 in \( \text{Cl}_2 \) to -1 in \( \text{Cl}^- \). The change in oxidation state is from 0 to -1, indicating a gain of electrons.
Therefore, the change in oxidation state of the reducing agent (chlorine) is from 0 to -1.
The correct answer is option D: \(0\) to \(+1\).
