Question

Aluminium hydroxide, $Al(OH{)}_3$ is insoluble in water, but dissolves readily in both acidic and basic solutions. Such behaviour is characteristic of

• A. amphoteric behaviour
• B. a buffer
• C. hydrophilic behaviour
• D. none

Answer 1

Answer: (A)

amphoteric behaviour

Aluminium hydroxide is amphoteric. Because it reacts with both acids and bases. Like any conventional base, the OH radical in Al(OH)3 neutralizes H+ to make water and an aluminium salt. $Al(OH{)}_3$ solid will also react with excess OH– to dissolve and form the complex ion $\left[Al\right(OH{)}_4{]}^{-}$.