Determination of first and second hydrolysis constants for lead
Publisher
The University of Arizona.Rights
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.Abstract
Differential 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.Type
textThesis-Reproduction (electronic)
Degree Name
M.S.Degree Level
mastersDegree Program
Graduate CollegeHydrology and Water Resources