Final answer:
The given elementary reaction N₂O₂(g) + O₂(g) → 2NO₂(g) is option b) bimolecular reaction. The molecularity of the reaction N₂O₂(g) + O₂(g) → 2NO₂(g) is bimolecular, as two reactant molecules participate in this single elementary step.
Step-by-step explanation:
The molecularity of the elementary reaction N₂O₂(g) + O₂(g) → 2NO₂(g) indicates the number of reactant molecules that collide and react in a single elementary step. In this reaction, two molecules, N₂O₂ and O₂, combine to form the product. Therefore, this reaction is considered to be bimolecular since it involves the collision between two reactant molecules.
It is important to distinguish between the overall reaction and an elementary step. An elementary step is considered to be a single reaction event without any intermediate steps. Termolecular reactions, which involve three molecules colliding simultaneously, are much less common due to the low probability of three molecules colliding with the correct orientation at the same time. Our reaction involves two molecules coming together, and thus, it is bimolecular.
Since there are two reactant molecules colliding with each other (N₂O₂ and O₂), this reaction is bimolecular. The molecularity of an elementary reaction refers to the number of reactant species involved in the reaction, and in this case, it involves two molecules, making it a bimolecular reaction.