Solution: We have seen a number of reactions in which a single reactant forms products. For example, consider the following first-order reaction: CH₃NC(g) → CH₃CN(g). However, we also learned that gas-phase reactions occur through collisions.One possible explanation is that two molecules of CH₃NC collide with each other and form two molecules of the product in a single elementary step. If that were the case, what reaction order would you expect?