.Dissolve in both acidic and basic solutions Al(OH)3(s)+3H"(aq)-Al(aq)+3H2O(1) Al(OH)(s)+OH (aq)-Al(OH)(aq) .Dissolve in ammonium salt solutions Example: Mg(OH)2 Mn(OH)2 K 5.1×10-12 2.1X1013 Mg(OH)2(s)-Mg(aq)+20H (aq) NH(aq)+OH (aq)=NH3H2O(aq) J↓J<K So does dissolving Mn(OH)2(s)in ammonium salt solution •Dissolve in both acidic and basic solutions Al(OH) (s) OH (aq) Al(OH) (aq) 3 4 - - + Al(OH) (s) 3H (aq) Al (aq) 3H O(l) 2 3 3 + + + + •Dissolve in ammonium salt solutions 2 Mn(OH) 2 Example ： Mg(OH) 12 13 5.1 10 2.1 10 - - Ksp × × Mg(OH) (s) Mg (aq) 2OH (aq) 2 2 + + - + - NH (aq) OH (aq) NH H O(aq) 4 3 2 +  J  J < Ksp So does dissolving Mn(OH)2 (s) in ammonium salt solution