Markownikoff's Rule: Why Does it Happen?

[Saoist]

looked in books/googled for info about this...i know what it IS, but don't understand why it happens. anyone?

 

[movies]

Originally it was based on empirical evidence (it was just the product that you got from certain reactions) and was used as a predictive tool. It can be rationilized by thinking about the intermediates of a reaction mechanism. If a carbocation is formed then it will be more stable at the more substituted carbon and therefore a nucleophile would be more likely to attack at that position.

 

[net_nubie]

Well, I ain't sure of this but consider a 1-Methyl-2-butene. When HCl adds across the double bond, Cl radical will attract the electrons of the C=C towards itself creating a partial +ve charge on the C atoms. This partial positive charge is handled better by a 3rd degree C atom than the 2nd degree C atom. Thus the -ve part of the addendum will go the the C with more substituents, which is the Markonikov's rule.