Amphoteric Substance Define(loosely) can react as either an acid or base under different circumstances Normally it is a poly-protic weak acid or base EXample NaHCO3 HCl NaCl H2CO3 NaHCO3 NaoH> Na2CO3+ H2O Na2HPO4, NaH2PO HO Fe(H2O)2+,A(H2O)3+,N(H2O)5(OH) However, even a strong acid may behave as a base, when it encounters with a stronger acid 6Amphoteric Substance z Define (loosely): can react as either an acid or base under different circumstances z Normall y py it is a pol y - protic weak acid or base z Example: „ NaHCO 3 + HCl Æ NaCl + H NaCl + H 2CO 3 NaHCO 3 + NaOH Æ Na 2CO 3 + H 2 O „ Na 2HPO 4, NaH 2PO 4 „ H 2 O „ Fe(H 2O)2+, Al(H 2O)3+, Ni(H 2O) 5(OH) + z However even a However, even a “strong acid strong acid ” may behave as a may behave as a base, when it encounters with a stronger acid. 6