Which of the following chemical processes involves a homogeneous catalyst?
The reduction of NO(g)\text{NO}(\text{g})NO(g) by CO(g)\text{CO}(\text{g})CO(g) over a solid platinum-palladium catalytic converter.
The reaction of gaseous SO2\text{SO}_2SO2 and O2\text{O}_2O2 in the Contact process using a solid vanadium(V) oxide catalyst.
The autocatalytic oxidation of aqueous ethanedioate ions (C2O42−\text{C}_2\text{O}_4^{2-}C2O42−) by acidified manganate(VII) ions (MnO4−\text{MnO}_4^-MnO4−).
The industrial hardening of vegetable oil using hydrogen gas and a solid nickel catalyst.