JEE Main · 2019 · 09 Apr 2019 · Shift 2 · p-Block Elements

Down the group the oxides of group 13 shift steadily from acidic through amphoteric to basic as metallic character grows. Boron, the least metallic, gives an acidic oxide, so $\mathrm{B}{}_2\mathrm{O}{}_3$ is acidic and statement I holds. Aluminium and gallium are more metallic, and $\mathrm{Al}{}_2\mathrm{O}{}_3$ and $\mathrm{Ga}{}_2\mathrm{O}{}_3$ dissolve in both acids and bases, so they are amphoteric and statement II holds. Indium and thallium, the most metallic of the group, give basic oxides, so statement III holds too. All three statements are correct.