Markovnikov's Rule applies to the electrophilic addition of asymmetric reagents (like $HBr$) to asymmetric alkenes.

• Rule: The positive part of the reagent ($H^{+}$) adds to the carbon atom of the double bond that already has the greater number of hydrogen atoms.
• Mechanism: The reaction proceeds through a carbocation intermediate.
• In Propene ($C{H}_3-CH=C{H}_2$), $H^{+}$ adds to $C1$, forming a Secondary carbocation ($C{H}_3-C{H}^{+}-C{H}_3$), which is more stable than a primary one. Subsequent $B{r}^{-}$ attack yields 2-Bromopropane.