For which type of reactions, order and molecularity have the same value?


For an elementary reaction, order is same as molecularity. Elementary reactions are those reactions which occur in a single step.


Suppose there are 2 reactants A and B which form a product C. Then


A+B C


Rate is determined by,


Rate = k[A]1[B]1


Order of the reaction is 2.


Molecularity of the reaction is also 2 as there are total 2 molecules of reactants that are reacting for the formation of a product C.




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