The kinetics of photoinduced electron transfer reaction of methylene blue (MB) and titanium trichloride was investigated in water and different aqueous–alcoholic solvents. The reaction is pseudo‐first order, dependent only on the concentration of titanium trichloride at a fixed concentration of MB. The effect of water and aqueous–alcoholic solvents was studied in the acidic pH range (4–7). It was observed that the quantum yield (ϕ) of the reaction increased with increase in polarity of the reaction medium. The quantum yield was high under acidic conditions and decreased with further increase in acidity. The addition of ions and increase in temperature increased the rate and quantum yield of the reaction. The absence of any reaction intermediate was confirmed by spectroscopic investigations. A mechanism for the reaction has been proposed in accordance with the kinetics of the reaction. The activation energy (Ea) was calculated by the Arrhenius relation. Thermodynamic parameters such as Ea, enthalpy change (ΔH), free energy change (ΔG), and entropy change (ΔS) were also evaluated.

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Ionic-Interactions of Potassium Iodide (KI) in binary solvent systems of edible oil (maize oil and sunflower oil) + N, N-dimethylformamide (DMF) were studied at different temperatures by viscosity method. The viscosities of KI in sunflower oil + DMF and maize oil + DMF were found to increase with the increase in concentration of edible oil and also with increase in concentration of KI from 1x10 -2 to 9x10 -2 mol.dm -3 . Ion-ion interaction and ion-solvent interaction were evaluated in terms of A and B coefficients of Jones-Dole equation and its applicability checked by Moulik equation. Ion-solvent interaction was found positive in edible oil + DMF solvent system. The parameter dB/dT was used as a criterion for the evaluation of structure-making or structure-breaking ability of salt (KI) in edible oil + DMF solvent system. It was concluded that KI behaves as a structure-breaker in edible oils + DMF solvent system.

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