Question

4. Consider the reaction F2 + 2NO2 → 2NO2F.
The following are proposed elementary steps for the reaction:
F2 + 2NO2 → NO2F + F + NO2 (slow)
F+NO2 → NO2F (fast)
a. Evaluate the proposed elementary steps. Why would these steps be more reasonable than the complete reaction in one step?

b. Does the reaction have any intermediates? If not, explain why. If so, identify the intermediates.

I have no idea how to approach part a other than with a generic answer that reactions with multiple steps can increase the reaction rate. For part b, I thought F and NO2 would be intermediates given that they can be canceled out.

Answer 1

a) it is always more Probable to have a bi-molecular reaction than a three molecules colliding in the right direction and the right energy. In this case looks like one F2 molecule will collide with one NO2 and produce a very reactive intermediary F that in the fast elementary step will react with other NO2 molecule. In the general equation one F2 has to collide with 2 NO2 at the same time.
b) I think that you have only one intermediate (reactants or products that doesn't show in the general equation). I will said the F is the only intermediate in the proposed mechanism. I will said that the NO2 it is a reactant, not a intermediate.