Electron transfer reaction of theobromine (hereafter referred to as TB) and permanganate ion has been studied using spectrophotometric technique under pseudo first-order conditions at T = 24, [H+] = 3.2 × 10–1 mol dm–3and I = 1.0 mol dm–3 (Na2SO4). Stoichiometric study depicted that two moles of TB were consumed by one mole of permanganate ion. The rate of the reaction is first order in both [TB] and [MnO4-] and second order overall. It was observed that, [H+] and ionic strength respectively enhanced the rate of the reaction in the range studied. Michaelis-Mentens analysis showed no evidence of intermediate complex formation. Added anions and cations were observed to catalyze the reaction rate. The reaction conforms to the rate law as shown below:     -d [MnO4-]/dt = (a+b [H+]) [TB] [MnO4-]                                                                                     where a = 0.041 dm3mol–1 s–1 and   b= 0.028 dm3mol–1 s–1. The reaction thus occurs by an outer-sphere pathway and plausible mechanism is proposed for the reaction.

We investigated the influence of soil properties on the availability or otherwise of micronutrients in agricultural soils impacted by inorganic and organic manures in the South-South Area of Nigeria. The levels of pH, organic matter (OM), cation exchange capacity (CEC), copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn) in the understudy soil were examined. The measured pH, OM, CEC, Cu, Fe, Mn and Zn levels revealed: 6.04±0.49, 17.68±4.78 %, 7.97±0.81 Cmolkg-1, 5.27±0.82 mgkg-1, 232.49±16.01 mgkg-1, 109.30±9.85 mgkg-1, and 8.40±1.15 mgkg-1, for pH, OM, CEC, Cu, Fe, Mn, and Zn, respectively. The values were within the acceptable limits set by national and international standards. The study revealed variable relationships between the soil properties and micronutrients in the studied soils at p < 0.05. Soil pH exhibited a strong negative association with all the micronutrients except Zn. However, a strong positive correlation (p< 0.10) was recorded between pH and Zn. OM showed a significant positive correlation (p< 0.10) with Fe, a weak positive correlation with Zn, and a non-significant negative correlation (p< 0.10) with Cu and Mn at p < 0.10. CEC exhibited a fair positive association with Fe and Zn, and a non-significant negative correlation (p< 0.10) with Cu and Mn. The principal component analysis (PCA) identified a combination of anthropogenic and natural impact and the impact of agrochemicals applied as the major factors influencing the properties determined in the studied soils. The study concluded that soil properties have a strong influence on the availability or otherwise of micronutrients in the soil.