Among the following organohalogen compounds, which one is classified as a vinylic halide and exhibit — Haloalkanes and Haloarenes Chemistry Question
Question
Among the following organohalogen compounds, which one is classified as a vinylic halide and exhibits the lowest reactivity towards a nucleophilic substitution reaction?
💡 Solution & Explanation
Let us classify and analyze the reactivity of each compound: A) Allyl chloride. Highly reactive in both $S_N1$ (resonance stabilized carbocation) and $S_N2$. B) Benzyl chloride. Also highly reactive due to resonance stabilization of the transition state and carbocation. C) Vinyl chloride ($CH_2=CH-Cl$). The halogen is directly attached to an $sp^2$ hybridized carbon. The lone pairs on chlorine participate in resonance with the pi bond ($CH_2=CH-Cl \leftrightarrow ^-CH_2-CH=Cl^+$). This imparts partial double bond character to the C-Cl bond, increasing bond strength and drastically lowering its reactivity towards nucleophilic substitution. D) tert-Butyl chloride. Highly reactive via $S_N1$ due to $3^\circ$ carbocation stability. Thus, vinyl chloride is the correct answer.