Naslov
Potentiometric Titration of Aluminium with Fluoride in Organic Solvent + Water Mixtures by Use of a Fluoride-selective Electrode

Autori
Radić, Njegomir ; Prugo Danica ; Bralić, Marija

Izvornik
Journal of electroanalytical chemistry and interfacial electrochemistry (0022-0728) 248 (1988), 1; 87-89

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
potentiometric titration ; aluminium ; fluoride ; acetate buffer ; organic solvent + water mixtures ; conditional formation constants of AlFt(3-t)- complexes

Sažetak
Potentiometric titrations of aluminium with fluoride in a background of acetate buffer (pH 5) in different organic solvent + water mixtures were carried out in order to study the effect of the organic solvent (namely: ethanol. methanol, n- propanol. tert-butanol and p-dioxane) on the titration curve and the analytical data. On the basis of potentiometric titration experiments the overall conditional formation constants of AlFt(3- t)- complexes have been calculated. The calculated constants increase with increasing vol.% of organic solvent for all mixtures tested. Among the solvents tested, p-dioxane yielded a greater potential break than the other solvents and the measurements in mixtures with this solvent and ethanol also showed the best precision. In p- dioxane-rich media a concentration of aluminium in the cell solution of 10-5 mol dm-3 was established as the detection limit for the potentiometric titration experiment. At a low concentration of aluminium, the stoichiometric ratio between aluminium and fluoride is constant for a narrow range of aluminium concentrations and can be determined by experiment only. The formation of aluminium hexafluoride complex in organic solvent+water mixtures may be accepted for the titration of higher concentrations of aluminium (> 10-5 mol dm-3).

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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