Stability Constants of Hydrazine Carboxylic Acid Complexes with Some Bivalent Metal Ions

Abstract

The proton-ligand stability constants of hydrazine carboxylic acid (HCA) and stability constants of its chelates with Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) have been determined, using Calvin-Bjerrum pH-metric method as modified by Irving and Rossotti in aqueous media at a constant ionic strength of 0.1M KCl and at a constant temperature (20 ± 0.2ºC). The stability constants of the complexes follow the order Cu(II) > Zn(II) > Ni(II) > Co(II) > Cd(II) which is in accordance with Irving-Williams natural order.