The $E^{\ominus}$ values for $Al^+/Al = +0.55 \text{ V}$ and $Tl^+/Tl = -0.34 \text{ V}$; $Al^{3+}/Al = -1.66 \text{ V}$ and $Tl^{3+}/Tl = +1.26 \text{ V}$. The incorrect statement among the following is:

Due to the inert pair effect in the heavier group 13 elements, the +1 oxidation state is much more stable than the +3 state for Thallium (Tl). As a result, $Tl^{3+}$ has a strong tendency to accept electrons and get reduced to $Tl^+$, making it a strong oxidising agent, not a reducing agent. Therefore, the statement claiming '$Tl^{3+}$ is a better reducing agent than $Tl^+$' is completely incorrect. Furthermore, $Al^{3+}$ is much more stable than $Al^+$, making $Al^+$ unstable in solution, and Tl is more readily oxidized to $Tl^+$ than to $Tl^{3+}$ given their standard reduction potential values.