[Steenrod]

I learnt of the molecularity of a reaction.But can anyone please point out the practical utility of the concept?

[Borek]

It is one of the most important parameters required to describe reaction kinetics.

[Steenrod]

Can you give one example of its use?

[Borek]

http://en.wikipedia.org/wiki/Rate_equation

In most chemical processes you need to know the reaction kinetics to design the best approach that gives the highest yields in a shortest time.

[Babcock_Hall]

Suppose I have a desirable reaction that follows first order kinetics and an undesirable one that follows second order (or higher) kinetics that happens in parallel with the first-order reaction.  The only example I can think of at the moment would be protein folding versus protein aggregation, starting from the unfolded state as the reactant in either case.  There are probably others.  How could I alter the reaction conditions to favor the favorable over the unfavorable reaction?

Suppose a student sets up a second order reaction and mistakenly uses twice as much solvent has he or she should have done.  How much more slowly will this reaction proceed?

[curiouscat]

Suppose I have a desirable reaction that follows first order kinetics and an undesirable one that follows second order (or higher) kinetics that happens in parallel with the first-order reaction.  The only example I can think of at the moment would be protein folding versus protein aggregation, starting from the unfolded state as the reactant in either case.  There are probably others.  How could I alter the reaction conditions to favor the favorable over the unfavorable reaction?

Suppose a student sets up a second order reaction and mistakenly uses twice as much solvent has he or she should have done.  How much more slowly will this reaction proceed?

Not to be too pedantic, but it is worth noting that order must agree with molecularity only for elementary reactions.

So, @OP: Don't be misled into thinking that a second order reaction must be bimolecular.

[curiouscat]

I learnt of the molecularity of a reaction.But can anyone please point out the practical utility of the concept?

Another trick is, if you come across a tri-molecular or tetra-molecular reaction you can be pretty sure it is not an elementary reaction.

[Babcock_Hall]

steenrod, Can you confirm that you are interested in the concept of molecularity, as opposed to the concept of reaction order?

[Steenrod]

Yes, indeed I am interested in the applications of molecularity.Thanks!