1 Al3+ + 3OH- = Al(OH)3 (s) 2 Al(OH)3 + 3H+ = Al3+ + 3H2O 3 Al(OH)3 + OH- = AlO2- + 2H2O 4 AlO2- + H+ + H2O = Al(OH)3 (s) 5 Al3+ + 4OH- = AlO2- + 2H2O 6 AlO2-+ 4H+ = Al3+ + 2H2O