NAGHAM KH. KAREEM; ISMAIL KH. AL-HITTI
Abstract
:Cyanide and Sulphide ion – selective electrodes were successfully exploited in the determination of the : Thiosulphate , Sulphite , Sulphide , Dithionite and Disulphite individually ...
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: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 .