p-Block Elements-I 1 Question 1
1. The correct statements among I to III regarding group 13 element oxides are:
(2019 Main, 9 April II)
I. Boron trioxide is acidic.
II. Oxides of aluminium and gallium are amphoteric.
III. Oxides of indium and thallium are basic.
(a) I, II and III
(c) I and II only
(b) I and III only
(d) II and III only
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Answer:
Correct Answer: 1. (a)
Solution:
- All the given statements are correct. For group 13 elements, the acidic nature of oxides decreases and the basic nature of oxides increases on moving from $\mathrm{B}$ to $\mathrm{Tl}$. This is because as we move down the group, the atomic size of elements goes on increasing, whereas the ionisation energy decreases, due to which the strength of metal oxide (MO) bond goes on decreasing. Thus, boron trioxide or boron oxide is acidic and reacts with basic oxides to give metal borates. Aluminium and gallium oxides are amphoteric while oxides of indium and thallium are basic in nature.
