The acid-catalyzed hydrolysis of the organopalladium complex [Pd(CNN)P(OMe)(3)]BF4 species was monitored spectrophotometrically at different sulfuric acid concentrations (3.9 and 11.0 M) in 10% v:v ethanol-water over the 25-45 degrees C temperature range and in 30% and 50% (v/v) ethanol-water at 25 degrees C. Two acidity regions (I and II) could be differentiated. In each of the two regions the kinetic data pairs yielded two different rate constants, k(1obs) and k(2obs) the former being faster. These constants were fitted by an Excess Acidity analysis to different hydrolyses mechanisms: A-1, A-2, and A-S(E)2. In region I ([H2SO4] < 7.0 M), the k(1obs) values remained constant k(1obs)(av) = 1.6 x 10(-3) s(-1) and the set of k(2obs) values nicely matched an A-S(E)2 mechanism, yielding a rate-determining constant k(0,ASE2) = 2.4 x 10(-7) M-1 s(-1). In region II ([H2SO4] > 7.0 M), a switchover was observed from an A-1 mechanism (k(0,A1) = 1.3 x 10(-4) s(-1)) to an A-2 mechanism (k(0,A2) = 3.6 x 10(-3) M-1 s(-1)). The temperature effect on the rate constants in 10% (v/v) ethanol-water yielded positive Delta H-double dagger and negative Delta S-double dagger values, except for the A-1 mechanism, where Delta S-double dagger adopted positive values throughout. The solvent permittivity effect, epsilon(r), revealed that k(lobs)(av), and k(0,A2) dropped with a fall in epsilon(r), whereas the k(0,ASE2) value remained unaffected, The set of results deduced is in line with the schemes put forward.