In the reaction of 2-bromobutane in a solution of sodium ethoxide and ethanol, the products will be 2-butene and 1-butene in a ratio of approximately 7:3.  
In the reaction of 2-bromobutane in a solution of sodium ethoxide and ethanol, the products will be 2-butene and 1-butene in a ratio of approximately 7:3.  Essentially the opposite of Markovnikoff addition, it allows for the prediction of chemical products upon the elimination reaction of an alkyl halide.  FTP, name this rule which states that the more highly substituted alkene will prevail in such a reaction, and which was proposed in 1875 by its eponymous Russian chemist.
In the reaction of 2-bromobutane in a solution of sodium ethoxide and ethanol, the products will be 2-butene and 1-butene in a ratio of approximately 7:3.  
Zaitsev's rule