Question

Consider the following Statement-I : \( \text{Al}_2\text{O}_3 \) is amphoteric in nature. Statement-II : \( \text{Tl}_2\text{O}_3 \) is more basic than \( \text{Ga}_2\text{O}_3 \). The correct answer is

• A. Both statement-I and statement-II are correct
• B. Both statement-I and statement-II are not correct
• C. Statement-I is correct, but statement-II is not correct
• D. Statement-I is not correct, but statement-II is correct

Hint:

- Amphoteric oxides react with both acids and bases (e.g., Al\(_2\)O\(_3\), ZnO, BeO, SnO, PbO). - Trends in acidic/basic nature of oxides in the p-block: - Across a period (left to right): Basicity decreases, acidity increases. - Down a group: Basicity increases, acidity decreases (for oxides of elements in the same oxidation state). - For Group 13 oxides (M\(_2\)O\(_3\)): - B\(_2\)O\(_3\) (acidic) - Al\(_2\)O\(_3\) (amphoteric) - Ga\(_2\)O\(_3\) (amphoteric, more basic than Al\(_2\)O\(_3\)) - In\(_2\)O\(_3\) (basic) - Tl\(_2\)O\(_3\) (strongly basic) Note: Thallium also forms a stable Tl\(_2\)O which is even more basic.

Answer 1

The Correct Option is A

Statement-I: \( \text{Al}_2\text{O}_3 \) is amphoteric in nature.
Aluminium oxide (\( \text{Al}_2\text{O}_3 \)) can react with both acids and bases.
- Reaction with acid (e.
g.
, HCl): \( \text{Al}_2\text{O}_3 + 6\text{HCl} \rightarrow 2\text{AlCl}_3 + 3\text{H}_2\text{O} \) (acts as a base).
- Reaction with base (e.
g.
, NaOH): \( \text{Al}_2\text{O}_3 + 2\text{NaOH} + 3\text{H}_2\text{O} \rightarrow 2\text{Na}[\text{Al(OH)}_4] \) (sodium aluminate) (acts as an acid).
Since it reacts with both acids and bases, \( \text{Al}_2\text{O}_3 \) is amphoteric.
So, Statement-I is correct.
Statement-II: \( \text{Tl}_2\text{O}_3 \) is more basic than \( \text{Ga}_2\text{O}_3 \).
Gallium (Ga) and Thallium (Tl) are both in Group 13.
Ga is in Period 4, Tl is in Period 6.
Down a group, metallic character generally increases, and the basicity of oxides tends to increase (while acidity decreases).
- \( \text{B}_2\text{O}_3 \) is acidic.
- \( \text{Al}_2\text{O}_3 \) is amphoteric.
- \( \text{Ga}_2\text{O}_3 \) is amphoteric (though predominantly acidic character is less than Al\(_2\)O\(_3\), more basic).
- \( \text{In}_2\text{O}_3 \) is basic.
- \( \text{Tl}_2\text{O}_3 \) is basic.
As we go down Group 13, the oxides become more basic.
Thallium is below Gallium.
Therefore, \( \text{Tl}_2\text{O}_3 \) is more basic than \( \text{Ga}_2\text{O}_3 \).
So, Statement-II is correct.
Both statements are correct.
This matches option (1).