Taking stability as the factor, which one of the following represents correct relationship?\

Question

Professor PC Thomas Classes · Answer

(b) : As we move down the group, the stability of the +3 oxidation state decreases while that of +1 oxidation state increases. Thus, stability order for +1 oxidation state is $\mathrm{Al}<\mathrm{Ga}$ $<\mathrm{In}<\mathrm{Tl}$ and +3 oxidation state is $\mathrm{Al}>\mathrm{Ga}>\mathrm{In}>\mathrm{Tl}$.\ Hence, the stability order is, $\mathrm{AlCl}_{3}>\mathrm{AlCl}$, $\mathrm{TlI}>\mathrm{TlI}_{3}$, $\mathrm{TlCl}>\mathrm{TlCl}_{3}$ and $\mathrm{InI}>\mathrm{InI}_{3}$.