Document Type : Research Paper
Authors
Anbar University - College of Science
Abstract
:Cyanide and Sulphide ion – selective electrodes were successfully exploited in the
determination of the : Thiosulphate , Sulphite , Sulphide , Dithionite and Disulphite individually and in
their mixtures by direct titration with iodine prepared in glacial acetic acid .The potentials responded
by these two electrodes were compared to those recorded by platinum electrode versus Calomel
reference electrode at different temperatures . Optimistic and encouraging results were obtained with
an accuracy of ±3.5% attributed to experimental errors . The three electrodes were successfully
applied to the monitoring of sulphur in three sulphur springs in Heet City . High concentrations of
sulphide were obtained which were matching the results obtained by other studies and assisting the
high efficiency of the iodimetric technique using iodine in glacial acetic acid .The positive potential
measurements of platinum electrode of the sulphur compounds and their negative free energy have
clarified that the iodimetric reactions are irreversible and completely displaced to the products which
were insured by positive entropy results .The negative potentials of cyanide and sulphide electrodes
have rendered the free energy values to be positive and negative values of entropy which indicated that
there is no passage of electrons through the cells and these two ion – selective electrodes do not
respond to oxidation – reduction potentials because of the high impedence of their membranes .
Main Subjects
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