Standard reduction potentials of the half reactions are given below: 
$$\begin{gathered} {\mathrm{F}}_2\left(\mathrm{g}\right)+2{\mathrm{e}}^{-}\to 2{\mathrm{F}}^{-}\left(\mathrm{aq}\right);{\mathrm{E}}^{\circ }=+2.85\mathrm{V} \\ {\mathrm{Cl}}_2\left(\mathrm{g}\right)+2{\mathrm{e}}^{-}\to 2{\mathrm{Cl}}^{-}\left(\mathrm{aq}\right);{\mathrm{E}}^{\circ }=+1.36\mathrm{V} \\ {\mathrm{Br}}_2\left(\mathrm{l}\right)+2{\mathrm{e}}^{-}\to 2{\mathrm{Br}}^{-}\left(\mathrm{aq}\right);{\mathrm{E}}^{\circ }=+1.06\mathrm{V} \\ {\mathrm{I}}_2\left(\mathrm{s}\right)+2{\mathrm{e}}^{-}\to 2{\mathrm{I}}^{-}\left(\mathrm{aq}\right);{\mathrm{E}}^{\circ }=+0.53\mathrm{V} \end{gathered}$$
The strongest oxidising and reducing agents respectively  are :