Nitric Acid Oxidations

Kurt was searching for information regarding the fundamentals of HNO₃ oxidations. In particular, he wanted to know how to maintain nitric acid's oxidative ability at moderate dilutions.

	RE: Nitric Acid Oxidations Dear Kurt,      Thanks for contacting Inorganic Ventures. I have not found a reference on this topic that goes into detail. However, the chemistry of nitric acid is of interest to Inorganic Ventures. The following is my understanding of this chemistry:      There are two reactions that nitric acid follows. In dilute solution the reaction is: NO3- + 4H+ + 3e- = NO + 2H2O; E0 = 0.96. Assuming you are working in dilute solution then the expression for ΔE (the reduction potential difference between two half cells) is: (ΔE) = 0.0591/n logK, where ΔE is form the oxidation reduction reaction equation, n is number of electrons, and logK is the equilibrium expression for the reaction.      In addition, the half reaction potential (E) for nitric acid may be estimated using the Nernst Equation, where E = E0 + 0.0591/3log[(H+)4 (NO3-)]/(PNO). This equation predicts an increase in the reduction potential (increase in oxidizing ability) as the acidity and molarity of nitric acid increases. Please keep in mind that this assumes a reaction that is not kinetically limited (irreversible). Please feel free to call with any questions.     Paul R. Gaines, Ph.D. Serving you in chemistry