Consider the following reduction processes: Al^3++3 e^- → Al ( s ), E^°=-1.66 V; Fe^3++ e^- → Fe^2+, E^°=+0.77 V; Co^3++ e^- → Co^2+, E^°=+1.81 V;…

Consider the following reduction processes : $$\begin{aligned} & \mathrm{Al}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Al}(\mathrm{~s}), \mathrm{E}^{\circ}=-1.66 \mathrm{~V} \\ & \mathrm{Fe}^{3+}+\mathrm{e}^{-} \longrightarrow \mathrm{Fe}^{2+}, \mathrm{E}^{\circ}=+0.77 \mathrm{~V} \\ & \mathrm{Co}^{3+}+\mathrm{e}^{-} \longrightarrow \mathrm{Co}^{2+}, \mathrm{E}^{\circ}=+1.81 \mathrm{~V} \\ & \mathrm{Cr}^{3+}+3 \mathrm{e}^{-} \longrightarrow \mathrm{Cr}(\mathrm{~s}), \mathrm{E}^{\circ}=-0.74 \mathrm{~V} \end{aligned} $$ The tendency to act as reducing agent decreases in the order :