Determination of equilibrium constant of ascorbic acid and benzoic acid at different temperature and in aqueous and non-aqueous media.
Dissociation constant studies of ascorbic acid and benzoic acid has been carried out potentiometrically at various temperature from 25 to 50 degrees C and in 10, 20, 30 and 40 percent dioxane-water solvent system at 25 degrees C. Effect of temperature and solvent concentration on pKa values has been observed. The resolution of acid strength in dioxane-water relative to that in water has been determined for both compound by plotting pKa values vs percent composition of solvent. The results shows greater resolution in non-aqueous media as compare to aqueous media. Data obtained is analyzed by Computer program written in GW-Basic for calculation of pKa values for monobasic acid.
Saeeduddin
National Centre of Excellence in Analytical Chemistry, Allama I.I. Kazi Campus, University of Sindh, Jamshoro, Pakistan.
Khanzada
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Mufti
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