Rapid-scan stopped-flow kinetic studies show that the multielectron oxidation of coordinated ammonia in cis-[Ru(bpy)(2)(NH3)(2)](2+) by acidic (pH 0.5-1.3) aqueous chlorine provides the nitrosyl complex cis-[Ru(bpy)(2)(NH3)-(NO)](3+) as the final product. The first step in this process involves the metal-centered oxidation of cis-[Ru(bpy)(2)-(NH3)(2)](2+) to cis-[Ru(bpy)(2)(NH3)(2)](3+), and the rate law for this process is -d[Ru(II)]/dt = 2k(1)[Ru(II)][Cl-2] with the second order rate constant, k(1), as (1.1 +/- 0.1) x 10(3) M(-1) s(-1) . Independent studies conducted on the cis-[Ru(bpy)(2)-(NH3)(2)](3+) complex show that conversion to the nitrosyl complex follows an A --> B --> C type consecutive pathway with k(slow) and k(fast) components, respectively. In the pH range of 0.5-2.8, the k(slow) process follows a competitive pathway where both Cl-2 and HOCl react with deprotonated coordinated ammonia. The rate law for the k(slow) process has the form k(slow) = {k(2)[H+][Cl-] + k(3)K(Cl)/(K-Cl + [H+][Cl-])}([Cl-2](tot)/[H+]), where K-Cl corresponds to the equilibrium constant for the hydrolysis of Cl-2. The rate constant k(2), corresponding to the Cl-2 term, is 6.5 +/- 0.3 s(-1) while the rate constant k(3), corresponding to the HOCl reaction, is 2.0 +/- 0.2 s(-1). The k(fast) process involves further oxidation of intermediate B by Cl-2. The intermediate of this reaction is speculated as either a nitrene, nitrido, or chloroamine complex. The kinetic studies indicate that the conversion of this unidentified intermediate to the final nitrosyl complex proceeds through a fast preequilibrium, involving deprotonation of the intermediate, followed by a direct attack by Cl-2. The rate law corresponding to the k(fast) process has the form k(fast) = [k(4)K(int)[Cl-2](tot)[H+][Cl-]]/[{K-int + [H+]}{[H+][Cl-] + K-Cl}], the equilibrium constant K-int for the deprotonation process is 0.11 +/- 0.04 M, and the rate constant k(4) is (7.8 +/- 1.5) x 10(2) M(-1) s(-1).