Answer
$I^-$ is oxidized and $Cl_2$ is reduced.
Work Step by Step
1. Rewrite the equation to show the ions and the atoms:
$Cl_2(g) + 2K^+(aq) + 2I^-(aq) --\gt 2K^+(aq) + 2Cl^-(aq) + I_2(s)$
2. Analyze what happens to each atom/ion during the reaction.
During this process, These are the charge increases/decreases:
$I^- --\gt I^0$: The increase in charge indicates that $I$ is oxidized.
$Cl^0 --\gt Cl^-$: The decrease in charge indicates that $Cl$ is reduced.
