Ruthenium (Ru) is a strong oxidation catalyst for organic compounds typically in the form RuO_4(aq) represented as H₂RuO_5(aq), but it is a stoichiometric catalyst because it is reduced during the oxidation of the organic species. Ru species also undergo redox reactions with water and dissolved oxygen. Assume ideal solutions.

(a) Show that RuO_4(s) is not stable in contact with an air saturated solution of water and that it will revert to RuO_2(s), independent of pH.

(b) Show that the solubility of H₂RuO_5(aq) is independent of pH in an aqueous solution saturated with air at 1 bar in contact with RuO_2(s). Calculate the concentration of H₂RuO_5(aq) that would exist at equilibrium.

(c) Consider the equilibrium of RuO₄^–_(aq) and H₂RuO_5(aq) in the presence of RuO_2(s). Determine the coefficients for the equation

(d) Consider the equilibrium of RuO₄^–_(aq) and RuO₄^2–_(aq) in the presence of RuO2(s). Determine the coefficients for the equation

Transcribed Image Text:

log [H₂RuO,ja/[RuO4] = b + c(pH).