$∆{\mathrm{\text{G}}}^{\mathrm{\text{o}}}=-\mathrm{\text{n}}\mathrm{\text{F}}{\mathrm{\text{E}}}^{\mathrm{\text{o}}}$

if ${\mathrm{\text{E}}}^{\mathrm{\text{o}}}=\mathrm{\text{p}}\mathrm{\text{o}}\mathrm{\text{s}}\mathrm{\text{i}}\mathrm{\text{t}}\mathrm{\text{i}}\mathrm{\text{v}}\mathrm{\text{e}};$then $∆{\mathrm{\text{G}}}^{\mathrm{\text{o}}}=\mathrm{\text{n}}\mathrm{\text{e}}\mathrm{\text{g}}\mathrm{\text{a}}\mathrm{\text{t}}\mathrm{\text{i}}\mathrm{\text{v}}\mathrm{\text{e}}$,

For those, conversions whose ${\text{E}}^{\text{o}}$ values are more positive are more favourable.
As we can see from then electrode potential data, that reduction of ${\mathrm{Al}}^{+}$ is spontaneous, but reduction of ${\mathrm{Tl}}^{+}$ is not. So, we can conclude from this that $\text{T}{\text{l}}^{+}$ is more stable than $\text{A}{\text{l}}^{+}$