This study determines the activation energy parameters for the hydrolysis of acetic anhydride in water/tetrahydrofuran solutions. These values are needed for studies to quantify the effect of the bulk electrostatic environment solvent-solute interactions on the hydrolysis reaction rate. Hydrolysis of an acetic anhydride with water or under basic conditions yields acetic acid. The current study is based on simple hydrolysis of acetic anhydride which produces acetic acid decreasing the pH over time. Simple hydrolysis is monitored by measuring pH versus time at temperatures ranging from 20.0 to 35.0 oC and mole fraction of water ranging from 0.75 to 1.00. Measuring pH over time has advantages over other methods such as conductivity, UV-vis spectroscopy, temperature scanning, FTIR, calorimeter as it is simple, inexpensive and reproducible. Experimental results were used to determine activation enthalpy and entropy for hydrolysis of acetic anhydride using tetrahydrofuran as the co-solvent. These values were determined using the Eyring rate equation under iso-mole fraction and isothermal conditions. Analysis was performed to determine if the activation enthalpy and entropy are temperature dependent. Eyring plots are expected to be linear for iso-mole fractions and isothermal conditions of tetrahydrofuran.