Sulfur dioxide is oxidized to sulfur trioxide in the following sequence of reactions: 2SO2 (g) + 2NO2 (g) ---> 2SO3 (g) + 2NO (g) [[[2nd sequence]]] 2NO (g) + O2 (g) ---> 2NO2 (g). (Part A) Write the chemical equation for the overall reaction. (Part B) Identify any molecule that acts as a catalyst in this reaction. (Part C) Identify any molecule that acts as an intermediate in this reaction.