Complexometric Determination of Chromium(III) from Binary and Ternary Mixtures Using 3-Hydroxy-3-Phenyl-1-m-Nitrophenyltriazenes as Metallochromic Indicator

Abstract

A method for the use of 3-hydroxy-3-phenyl-1-m-nitrophenyl-triazene
as metallochromic indicator for the complexometric determination of
chromium(III) and for the complexometric determination of Cr(III) by
kinetic masking in presence of other metal ions viz. Fe(IlI), Cu(II) and
Ni(II) in binary mixtures containing ion pairs Cr(III), Fe(III), Cr(III), Cu(II)
and Cr(III)-Ni(II) has been described. The study has been further extended
to determine Cr(III) in ternary mixtures cotaining any of the three ions,
viz., Cr(III)-Fe(III)-Cu(II), Cr(III)-Fe(III)-Ni(II) and Cr(III)-Cu(III)-Ni(II).
The amount of metal ions found was in good agreement with the amount
of metal ions actually present; so the determinations are quite accurate.
For the sake of comparison parallel titrations were carried out using xylenol
orange as indicator. This establishes use of hydroxytriazene as metallochromic
indicator for Cr(III) determination.