Question

Markownikoff addiion of $HCl$ to propene involves:

• A. isomerization of $1$$-chloropropane$
• B. formation of an $isopropyl$ cation
• C. formation of propyl cation
• D. initial attack by a chloride ion

Answer 1

The correct option is B formation of an $isopropyl$ cation

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

The chemical basis for Markovnikov's Rule is the formation of the most stable carbocation during the addition process.

$C{H}_{3}CH=C{H}_2$ propene on addition of $HCl$ forms most stable carbocation (isopropyl cation) $C{H}_3{CH}^{+}-C{H}_2$ followed by addition of chlorine ion.