The hydroxide of aluminium is more acidic than that of boron
B
The hydroxide of boron is basic, while that of aluminium is amphoteric
C
The hydroxide of boron is acidic, while that of aluminium is amphoteric
D
The hydroxides of boron and aluminium are amphoteric
Text Solution
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The correct Answer is:
C
Boric acid is a hydroxide of boron, which is soluble in water and behaves as a weak monobasic acid. It does not donate proton like most acids. But rather it accepts `OH^(-)` ions. It is therefore, a Lewis acid `B(OH)_3 +2H_2O harr 2H_3O^(+) +[B(OH)_4]^(-)` Hydroxide of aluminium `[Al(OH)_3]` is amphoteric. It reacts principally as a base, that is, it reacts with acids to form salts that contain the `[Al(H_2O)_6]^(3+)` ion. However, `Al(OH)_3` shows some acidic properties when it is dissolved in NaOH forming sodium aluminate.
