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CH1012
ALUMINIUM HYDROXIDE
Aluminium hydroxide Al(OH)3  is amphoteric, so is gallium hydroxide Ga(OH)3
(ie. behaves as a base towards strong acids and as an acid towards strong bases):
 ie.   Al(OH)3                  ®     Al3+  +  3OH- 
 \    Al(OH)3  +  3H+     ®      Al3+aq  +  3H2O
&      Al(OH)3  +  H2O    ®     Al(OH)4-  +  H+ 
\     Al(OH)3  +  OH-     ®     Al(OH)4- 
In these examples Al(OH)3 acts indirectly as both a proton acceptor & a proton donor.