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

Published

March 1, 2003

Author(s)

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

Abstract

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 K_eq = (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.

Citation

Journal of Physical Chemistry A

Volume

107

Issue

No. 12

Pub Type

Journals

Keywords

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

Citation

Poskrebyshev, G. , Huie, R. and Neta, P. (2003), The Rate and Equilibrium Constants for the Reaction NO₃ + Cl^- {forward arrow over back arrow} NO₃^- + Cl in Aqueous Solutions, Journal of Physical Chemistry A (Accessed April 27, 2024)