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Kinetics and mechanism of oxidation of formic acid by bismuth(V) in aqueous phosphoric acid medium
Author(s) -
Dubey Sapna,
Devra Vijay,
Binyahia A. R.,
Sharma P. D.
Publication year - 2000
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/1097-4601(2000)32:8<491::aid-kin7>3.0.co;2-4
Subject(s) - bismuth , formic acid , chemistry , phosphoric acid , aqueous solution , stoichiometry , kinetics , inorganic chemistry , reactivity (psychology) , nuclear chemistry , organic chemistry , quantum mechanics , medicine , physics , alternative medicine , pathology
The solution of bismuth(V) was prepared by digesting sodium bismuthate in aqueous phosphoric acid (3.0 mol dm −3 ), the resulting pink colour solution absorbs in the visible region at 530 nm (640 dm 3 mol −1 cm −1 ). The stoichiometry of the oxidation of formic acid by bismuth(V) corresponds to the reaction as represented by the Eq. ( 1). 1$$\rm Bi^{V}+HCO_{2}H\longrightarrow Bi^{III}+2\ H^{+}+CO_{2}$$ The observed kinetic rate law is given by the Eq. ( 2); 2$$\rm -{\mit{d}\rm [Bi^{V}]\over\mit{dt}}=\left( \mit{k}_{1}+{\mit{k} _{2}\rm\ K_{a}\over\rm [H^{+}]}\right) \rm{[Bi^{V}]\ [HCO_{2}H]}$$ where Bi V and [HCO 2 H] are the gross analytical concentrations of bismuth(V) and formic acid respectively. A plausible reaction mechanism corresponding to the rate law (2) has been proposed. Also the pattern of reactivity of bismuth(V) in HCIO 4 −HF mixture and H 3 PO 4 respectively has been compared. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 32: 491–497, 2000