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Spectrophotometric Studies of Nickel(II) and Copper(II) Chelates of p ‐(2‐Hydroxy‐1‐Naphthylazo)‐Benzenesulphonate
Author(s) -
Hseu TongMing,
Lin LangSheng,
Sun HuiHsien
Publication year - 1970
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.197000028
Subject(s) - chemistry , chelation , nickel , copper , stoichiometry , ionic strength , stability constants of complexes , metal , reagent , metal ions in aqueous solution , inorganic chemistry , aqueous solution , nuclear chemistry , organic chemistry
The ionization constant of p ‐(2‐hydroxy‐1‐naphthylazo)benzene‐sulphonate (Orange II) and the formation constants of the metal chelates of this reagent with Ni(II) and Cu(II) have been determined spectrophotometrically in aqueous solution at 25° and at an ionic strength of 0.10 M . The ionization constant of orange II was found to be p K a =10.95. Formation of orange II chelates with Ni(II) and Cu(II) was p H dependent, and the optimum p H range of the Ni(II) Chelate was at p H 9.2‐9.4, and Cu(II) chelate at 9.5‐9.7, respectively. The mole ratio of orange II to both of metal ions was found to be 2 to 1 stoichiometry. The formation constants (logK) of the Ni(II) and Cu(II) chelates were 12.50 and 16.11, respectively. The molar extinction coefficients and the photometric sensitivities of these chelates were determined.