69. Solving a chemistry problem

423. The reaction of saponification of ethyl acetate with an excess of sodium hydroxide in an aqueous medium was studied at a constant temperature. To determine the current alkali concentration, 100 cm3 samples were taken from the reaction mixture and titrated with a 0.0430 mol/L HCl solution. The table below shows the dependence of the volume of the acid solution, V, used for titration of the sample, on the reaction time. Determine the rate constant from these data, knowing that the reaction has a second order: the first for ethyl acetate and the first for OH– ions.

t, min 0 4.89 10.37 28.18 ∞
V, cm3 62.0 50.6 42.4 29.4 14.9