Case: Read the passage and answer the following questions A property of a reaction called molecularity helps in understanding its mechanism. The number of reacting species (atoms, ions, or molecules) taking part in an elementary reaction, which must collide simultaneously in order to bring about a chemical reaction is called molecularity of a reaction.

Why the reaction of high molecularity is rare?

Activation energy is very high Many body collisions are not favored energetically Very high concentration required for such reaction Many body collisions have low probability

Many body collisions have low probability

Reactions of higher molecularity (molecularity > 3) are rare. This is because a reaction takes place by collision between reactant molecules and as number of reactant molecules i.e. molecularity increases the chance of their coming together and colliding simultaneously decreases.