Given $E^{\circ }(\mathrm{F}{}_2/\mathrm{F}{}^{-})=2.87$, $E^{\circ }(\mathrm{Cl}{}_2/\mathrm{Cl}{}^{-})=1.36$, $E^{\circ }(\mathrm{Br}{}_2/\mathrm{Br}{}^{-})=1.09$, $E^{\circ }(\mathrm{I}{}_2/\mathrm{I}{}^{-})=0.54\mathrm{V}$. The strongest oxidising agent among the following is

Oxidising strength increases with the standard reduction potential. $\mathrm{F}{}_2$ has the highest $E^{\circ }$ ($2.87\mathrm{V}$), so it is the strongest oxidant and can oxidise every other halide ion. $\mathrm{Cl}{}^{-}$ and $\mathrm{I}{}^{-}$ are reduced forms and act only as reducing agents.