Question

Which one of the following statements about the Markownikoff rule is not true?

• A. In Markownikoff additions, the alkene $C$-atom with the most $H$ atoms will be protonated.
• B. When $HX$ adds to an asymmetrical alkene, the halogen attaches to the least substituted alkene C-atom
• C. When $HX$ adds to an asymmetrical alkene, the halogen attaches to the most substituted alkene $C$-atom
• D. When $HX$ adds to an asymmetrical alkene, the protonation leads to the most stable carbocation intermediate,

Answer 1

Answer: (B)

When $HX$ adds to an asymmetrical alkene, the halogen attaches to the least substituted alkene C-atom

Markovnikov's rule states that with the addition of an HX to an unsymmetrical alkene, the acid hydrogen (H) becomes attached to the carbon with fewer alkyl substituents and the halide group (X) becomes attached to the carbon with more alkyl substituents.

Alternatively, the rule can be stated that the hydrogen atom is added to the carbon with the greater number of hydrogen atoms while the X component is added to the carbon with the fewer number of hydrogen atoms.

Markovnikov's rule forms the most stable carbocation during the addition process.