Final answer:
The reaction N2O3(g) → NO(g) + NO2(g) is likely spontaneous under high temperature and low pressure due to the endothermic nature of reactions involving nitrogen oxides, based on the behavior of similar compounds.
Step-by-step explanation:
To determine under what conditions the reaction N2O3(g) → NO(g) + NO2(g) is spontaneous, one must consider both the thermodynamics and kinetics of the reaction, as well as the principles of Le Châtelier's law.
Considering similar reactions provided in the reference, reactions involving nitrogen and oxygen compounds, such as the formation of nitrogen monoxide and nitrogen dioxide, tend to be nonspontaneous at low temperatures and spontaneous at high temperatures due to their endothermic nature. An increase in temperature provides the necessary energy for these endothermic reactions to proceed.
In contrast, an increase in pressure does not favor the production of more gas molecules. Le Châtelier's principle suggests that increasing the pressure shifts the equilibrium to the side with fewer gas molecules, which in this case is towards the reactant N2O3. Therefore, the conditions that would make the reaction spontaneous are likely to be high temperature to provide the required energy and low pressure to allow the increase in gas molecules.
Without specific data on the reaction of N2O3, we base our inference on the behavior of similar nitrogen oxides and their reactions. The reaction given, 3 NO(g) → N2O(g) + NO2(g), has not been analyzed here for spontaneity since the temperature and pressure conditions for this reaction are not detailed.