Rate Constant for the Reaction of Cl<INF>2</INF>(aq) with OH<SUP>-</SUP>

The second-order rate constant (k<INF>2</INF>) for the aqueous-phase reaction Cl<INF>2</INF>(aq) + OH^- → HOCl + Cl^- was determined by measuring the uptake of gas-phase chlorine into water in a bubble train flow reactor. In making these measurements, we avoided some of the difficulties encountered in earlier studies. Data were obtained at 275, 293, and 303 K, yielding k<INF>2</INF> = (1.3 ± 0.5) × 10⁸ M^-1 s^-1, (6 ± 2) × 10⁸ M^-1 s^-1, and (8 ± 3) × 10⁸ M^-1 s^-1, respectively. The atmospheric relevance of the chlorine hydrolysis reaction is discussed.