Abstrait

A novel sensor as indicator electrode in potentiometric and conductometric acid-base titrations in aqueous solution

Nasser Abu Ghalwa, Mazen Hamada, Mohammed Al Askalany, Tagreed Siam

This work deals with the preparation of Ti/Co3O4/(SnO2+Sb2O3) modified electrode by thermal deposition of alloy Sn and Sb in titaniumsubstrate and its use as indicator electrode in potentiometric and conductometric acidbase titration in aqueous solution at 298.15 K. The E-pH curves are linear with slopes of (0.0503) at 298.15 K. This value is close to the theoretical value 2.303RT/2F (0.059 V at 298.15 K). The standard potential of these electrodes, E0, are computed with respect to the SCE as reference electrode. The recovery percentage for potentiometric and conductometric acid-base titration is calculated. The cell constant for pair electrode was determined. The specific conductance for standard KCl was determined and compared with that of glass conductive electrode. The variation of molar conductance with dilution for some common electrolytes was tested. Also the molar conductance at infinite dilution of some common electrolytes is determined by each conductive cell and conductive glass electrode. Three acids: acetic, propanoic and phosphoric acids were potentiometrically titrated with NaOH as titrants where acetic, hydrochloric and a mixture of acetic and hydrochloric acids was conductometrically titrated with NaOH as titrants in aqueous medium at 298.15 K using the prepared electrode.