Markovnikov's rule describes the addition of hydrogen halides to unsymmetrical alkenes and alkynes. It states that the negative part of the adding reagent or hydrogen atom will add to the carbon of the double or triple bond that has the fewest hydrogen atoms already attached. This leads to the halide or hydrogen attacking the most electropositive carbon. The addition produces either a haloalkene if an alkene was the starting material or a gem-dihaloalkane if an alkyne was used.

1. Markovnikov’s rule
Addition of hydrogen halide to unsymmetrical alkene / alkynes

2. Addition of hydrogen halide in unsaturated compounds proceed through
following possible ways:
Alkene/ alkynes
Symmetrical Un-symmetrical

3. Addition In Symmetrical Compounds
Symmetrical compound
o Have same no. of
hydrogen atoms attached
to both doubly/ triply
bounded carbon atoms
o Incoming Hydrogen can
bound to any of the
unsaturated carbon

4. Addition In Un-symmetrical compounds
& Markovnikov’s Rule
Markovnikov’s Rule states that:
“in the addition of an unsymmetrical reagent in unsymmetrical
alkene, the negative part of the adding reagent goes to that carbon,
constituting the double bond, which has least no. of hydrogen atom”
o Halide will attack on less electropositive carbon

5. or
“In the addition of hydrogen halide to the carbon-carbon double
bond of an alkene the hydrogen atom attaches itself to the
carbon atom of the double bond that already holds greater no.
of hydrogens”
o Hydrogen will attack on more electropositive carbon

6. Addition in Alkenes

7. Addition in Alkynes
gem-dihaloalkane
Alkyne
haloalkene