To determine which halogen (\(X_2\)) will predominantly form in the reaction \(Cu^{2+} + X^- → Cu_2X_2 + X_2\), we need to consider the redox potential of the halogens and their relative ability to oxidize copper ions.
The order of oxidizing power among the halogens is F2 > Cl2 > Br2 > I2. Thus, iodine has the least oxidizing power among common halogens like Cl2, Br2, and I2. This means iodine would be more easily reduced and tend to form in the reaction over time when compared to other halogens.
According to the reaction, copper (II) ions are reduced, and halide ions are oxidized. Iodine is less reactive compared to chlorine and bromine, thus making it the more stable form in such reactions, meaning it will easily form from iodide ions (\(I^-\)) being oxidized.
This explain why I2 will predominantly form in the given chemical reaction.
Correct Answer: I2