PublisherThe University of Arizona.
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AbstractDifferential Pulse Polarography is used to study complex formation between Pb(II) and hydroxide. Measurements have been made at four different temperatures (16.5°C, 20.5°C, 25.7°C, 28.8°C) and three different ionic strength (I= 0.05M, 0.1M, 0.3M), using total ion concentration= 0.02mM. The following values for 25.7°C and 0.05M were obtained: logKPbOH+ = 6. 81 _=!=_ 0. 08, logKPb(OH)2 = 11.61 _=!=_ 0. 07. Temperature dependence is expressed by the following relations: logKPboH+ = -6225.2 (1/T) + 27.64, logKPb(OH)2 = -7422 (1/T) + 36.39 (I=0.05M). Free energy, enthalpy, and entropy for both complexes are calculated using the corrected values for the ionic strength effects and then extrapolated to zero ionic strength. Total lead concentration changed with pH during titrations, due to adsorption on vessel walls; the calculated values for hydrolysis constants are independent of lead concentration.
Degree ProgramGraduate College
Hydrology and Water Resources