Markownikoff rule

Markownikoff Rule

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MarkowniKoff ‘s rule (M.K.Rule)-

“When an unsymmetrical reagent adds to an unsymmetrical alkene, the negative part of  the reagent  get  attached to that carbon atom which is  joined to lesser number of Hydrogen atom”.

Ex.1 )  Addition of  Halogen acid  to Propene : 


Ex,2 )  Addition of Halogen acid to alkynes :



Anti Markownikoff’s rule or Kharasch effect or peroxide effect-

The addition of any  polar molecule to any  unsymmetrical  alkene or  unsymmetrical  alkyne in the presence of oxygen or benzoyl peroxide takes place against the  M.K. rule . According  to this rule –

               When any polar molecule is added to any  unsymmetrical alkene in presence of any organic  peroxide, the negative part of molecule is added to that carbon atom which is connected to more Hydrogen atom than the other unsaturated carbon atom . This is known as peroxide effect.

Ex. Addition of Halogen acid to Propene :