Features of Electrolysis of Nitric Acid Solutions of Silver: I. Behavior of Ag(II) in HNO3 Solutions

The current efficiency of Ag(II) formation in the course of electrochemical oxidative dissolution of PuO₂ was determined. It approaches 72% at the anodic potentials from 1.9 to 2.1 V (vs. SHE) and the anodic current densities of 0.006-0.013 A cm^-2. The behavior of Ag(II) in 4 M HNO₃ at 8, 25, and 40°C was studied. The reaction of Ag(II) with water can be described by the equation d[Ag(II)]/dt = kapp[Ag(II)]ⁿ, where n 2 at 8-25°C and 2-1.5 at 39-41°C. The apparent rate constants of the reaction are 1.5 and 3.8 l mol^-1 min^-1 at 8.5°C and 25°C, respectively. At 39-41°C, the reaction order with respect to Ag(II) ranges from 2 to 1.5, and the rate constant is about 1.2 l^1/2 mol^-1/2 min^-1.