REACTION OF THE HYDRATED ELECTRON WITH WATER

The reaction of e-(aq) with water was studied as a function of temperature in hydrogen-saturated water and in deaerated formate solutions. The two systems gave similar results. The rate constant at 25-degrees-C is 1040 s-1, and the activation energy is 7.5 +/- 0.2 kcal/mol. This activation energy and a recent determination of the activation energy for the reverse process give DELTAH-degrees-298 = -1.4 +/- 0.2 kcal/mol for the reaction e-(aq) + H2O(liq) half arrow right over half arrow left H. + OH-, to be compared with an earlier value of -1.1 kcal/mol derived from the equilibrium of e-(aq) with NH4+. The earlier value is believed to be less susceptible to errors.