1990 Volume 6 Issue 5 Pages 721-725
The effect of complexing agents on the titration of chromium(VI) and copper(II) with iron(II) was studied. In general, iron(III) forms more stable omplexes than iron(II), so that the potential of the system Fe(III)/Fe(II) is lower in the presence of a complexing agent than in its absence. Thus the addition of a complexing agent increases the sharpness of the end point of titration with Iron(II). The presence of pyrophosphate improves the potential break at the equivalence point of chromium(VI) with Iron(II). The use of neocuproine together with pyrophosphate is very effective in the titration of copper(II) with Iron(II).