Markovnikov's Rule

Markovnikov's rule or Markownikoff's rule started that in addition to polar reagent to unsymmetrical alkene the negative part of the polar reagent (Cl, OH, F etc) is attached to the carbon having the lowest number of hydrogen while the positive part of the polar reagent (H,Na,Mg,Al etc) is attached to the carbon having the highest number of hydrogen. The rule was postulated by Vladimir Markovnikov.

 Explanation 
From the above diagram, the reactant which is prop-1-ene which unsymmetrical alkene, it's reacting with Hydrobromic acid (Hydrogen Bromide) which is the polar reagent. When this hydrogen bromide dissociate it yield H+ and Br-. The positive part of this polar reagent (H+) is attached to the carbon in between the double bond with highest number of hydrogen while the negative part of this polar reagent (Br-) is attached to the carbon in between the double with the lowest number of hydrogen. It's usually go with addition reactant.

 Anti-Markovnikov's Rule 
Anti-Markovnikov's rule oppose Markovnikov's rule completely. It occur in the presence of hydrogen peroxide (H2O2). 

Anti-Markovnikov's rule started that in addition polar reagent to unsymmetrical alkene the positive part of the polar reagent is attached to the carbon in between the double with lowest number of hydrogen while the negative part of the polar reagent is attached to the carbon in between the double having the highest number of hydrogen. 

References

Category:Organic chemistry