It is shown that, when considering the electrochemical behavior of oxalic a
cid (OA) on platinum, it is necessary to account for the presence of three
types of adsorbates of OA. It is established that kinetic parameters of the
OA electrooxidation are sensitive to the electrolyte's temperature and com
position, which explains contradictions in the literature data. The electro
oxidation reaction order by OA is 0.2-0.6 at pH 0.3-2.8 and depends on both
the potential and the OA concentration. Such order points to the participa
tion of the OA adsorption products in the rate-determining stage of the pro
cess. The OA electrooxidation reaction order by hydroxyl ions is 0.8 at ele
vated temperatures, pH 0.3-2.8, and a constant potential; at room temperatu
re, it diminishes to -0.4 in the oxygen range of potentials. The experiment
al data suggest that two OA oxidation processes occur in parallel (with and
without participation of adsorbed oxygen-containing species). The balance
between the rates of these processes is potential-dependent.