Uptake of NO 3 on KI solutions: rate coefficient for the NO 3 + I − reaction and gas-phase diffusion coefficients for NO 3

Abstract

Uptake of NO 3 by KI solutions was measured at 273 ± 1 K using a wetted-wall flow tube to determine the rate coefficient for the NO 3(aq) + I − reaction to be k = (4.6 ± 0.5) × 10 9M −1 s −1. It is suggested that the reaction of NO 3 with halide ions proceeds by electron transfer. Use of high concentration of KI enabled determination of the gas-phase diffusion coefficients of NO 3 in H 2O vapor, He, N 2 and O 2 to be, respectively, D NO 3 − H 2O = 120 ± 15, D NO 3 − He = 345 ± 25 D NO 3 − N 2 = 80 ± 15 and D NO 3 − O 2 = 80 ± 15 Torr cm 2s −1. These coefficients agree well with calculated values.