POTENTIOMETRIC STUDIES ON THE COMPOSITION OF NlCKEL FERROCYANIDE COMPLEX

The formation and precipitation of nickel ferrocyanide has been studied by potentiometrie titrations between nickel sulphate and potassium fcrrocyanide using ferri-ferrocyanide electrode both by the direct and the inverse methods The pint of inflection obtained from the maximum value of ∆E/∆C corresponds to the formation of a double salt having the composition 4Ni2Fe(CN)3. 3K4Fe(CN)2, with either of the substances used as the reagent. The potentiometrie curves have a regular shape ; a sharp break in potential occurs at the equivalence point and the titration results are accurate and reproducible. The effect of alcohol on the end-point as well as on the nature of curves has been studied