The probability of reaction with molecularity higher than three is very rare as molecularity defines the collision of reactant molecules due to which the reaction occurs. The two most important conditions for a reaction to occur are:

• Energy greater than activation energy.

• Proper orientation of reactant molecules at the time of collision

So, for a reaction having more than three molecules, the proper orientation is not possible that makes these reactions rare.

Rate = Pz_ABe^-Ea/RT

P= probability factor.