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The Rate and Equilibrium Constants for the Reaction NO3 + Cl- forward arrow over back arrow} NO3- + Cl in Aqueous Solutions



G A. Poskrebyshev, Robert E. Huie, Pedatsur Neta


The rate and equilibrium constants for reaction (1): NO3 + Cl- back arrow over forward arrow} Cl + NO3- in aqueous solutions were studied by pulse radiolysis. The formation and decay of the nitrate radical, NO3, and the dichloride radical, Cl2 -, in irradiated aqueous solutions containing nitric acid and chloride ions were followed under various conditions. Because of the complexity of the system, the rate and equilibrium constants were derived from modeling the experimental results with a complete set of formation and decay reactions. Among the decay reactions is the proposed rapid oxidation of Cl2 - to Cl2 by the NO3 radical. By taking the recently published value of k-1 = 1.0 108 L mol-1 s-1, we derive the forward rate constant k1 = (3.5 ± 0.5) x 108 L mol-1 s-1 and the equilibrium constant Keq = (3.5 ± 0.5) at an ionic strength between (0.1 and 1) mol L^-1^. In contrast with previous reports, no effect of ionic strength (up to 2 mol L^-1^) on the forward rate constant was observed.
Journal of Physical Chemistry A
No. 12


atmospheric chemistry, free radical, kinetics, nitrate radical, rate constant


Poskrebyshev, G. , Huie, R. and Neta, P. (2003), The Rate and Equilibrium Constants for the Reaction NO<sub>3</sub><sup> </sup> + Cl<sup>-</sup> {forward arrow over back arrow} NO<sub>3</sub><sup>-</sup> + Cl<sup> </sup> in Aqueous Solutions, Journal of Physical Chemistry A (Accessed May 22, 2024)


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Created February 28, 2003, Updated October 12, 2021