Potentiometric Investigation of the Weak Association of Sodium and Oxalate Ions in Aqueous Solutions at 25°C

Article

<< Previous

Next >>

Contents Vol 58(3)

doi:10.1071/CH04230

Potentiometric Investigation of the Weak Association of Sodium and Oxalate Ions in Aqueous Solutions at 25°C

Andrew Tromans ^A, Glenn Hefter ^A ^B, Peter M. May ^A

^A Chemistry Department, Murdoch University, Perth WA 6150, Australia.
^B Corresponding author. Email: g.hefter@murdoch.edu.au





	PDF (273 KB) $25



	Export Citation

Print

Australian Journal of Chemistry 58(3) 213–217 http://dx.doi.org/10.1071/CH04230
Submitted: 1 October 2004 Accepted: 19 January 2005 Published online: 15 March 2005

Abstract

The formation constant β(NaOx^-) of the extremely weak ion pair formed between sodium (Na⁺) and oxalate (Ox^2-) ions in aqueous solutions has been determined at 25°C as a function of ionic strength in tetramethylammonium chloride by Na⁺ ion-selective electrode potentiometry. The effects of trace Na⁺ impurities from all reagents were accounted for. An extrapolated value for β ^o of 6.6 ± 0.5 M^-1 was obtained at infinite dilution, which is in good agreement with literature values. Attempts to measure this constant in 1 M CsCl media gave a β(NaOx^-) value of 0.00 ± 0.06 M^-1, probably because of competition between Cs⁺ and Na⁺ for Ox^2-.