Kinetics of the acid hydrolysis of nitrito-complexes. Part II. Nitritopenta-aquochromium(III) ion

Abstract

The nitritopenta-aquochromium(III) ion has been prepared [λ_max. 563 mµ(ε_M 18·1)]. The compound rapidly aquates at all pH values, and is most stable in the pH range 3–4. The acid-catalysed hydrolysis was studied by the stopped-flow method, and the rate law was found to be: –d[Cr(H₂O)₅ONO²⁺]/dt=(k₁′[H⁺]+k₂′[H⁺]²)[Cr(H₂O)₅ONO²⁺]. At 25° and I= 1·0 (NaClO₄), k₁′= 10^{(15·22 ± 0·45)} exp(–20,360 ± 590)/RT l. mole^–1 sec.^–1, and k₂′= 10^{(11·24 ± 0·20)} exp(–14,450 ± 260)/RT l.² mole^–2 sec.^–1.