Question

Which of the following compounds do not undergo nucleophilic substitution reaction?

• A. Ethyl bromide
• B. Vinyl chloride
• C. Isopropyl chloride
• D. Benzyl chloride

Answer 1

The correct option is B Vinyl chloride

For a nucleophilic substitution to happen, the carbon to which the leaving group is attached should not only facilitate the attack of the nucleophile, but also allow the leaving group to depart. In vinyl chloride, the chlorine atom is attached to a more electronegative carbon because the carbon has a higher %s-character owing to $s{p}^2$ hybridization. All the other substrates have the halogen (leaving group) attached to an $s{p}^3$ hybridized carbon. So the carbon doesn't allow the leaving group to depart.