Which of the following oxides of Group 13 elements is predominantly basic in nature?

Step-by-step solution

Down the group in the p-block, the metallic character of elements increases, which leads to an increase in the basic nature of their oxides. In Group 13, B₂O₃ is acidic. Al₂O₃ and Ga₂O₃ are amphoteric in nature. The oxides of the heavier elements, In₂O₃ and Tl₂O₃ , are predominantly basic. Answer: Tl₂O₃