Question

The ease of dehydrohalogenation of alkyl halide with alcoholic $KOH$ is

• A. $3^\circ < 2^\circ < 1^\circ $
• B. $3^\circ >2^\circ >1^\circ $
• C. $3^\circ < 2^\circ >1^\circ $
• D. $3^\circ >2^\circ < 1^\circ $

Answer 1

Answer: (B)

Such dehydrohalogenation follow $E_{2}$ mechanism. The driving force of such reaction is the stability of alkene produced. Since, tertiary alkyl halide can give more substituted alkene, it reacts fastest followed by secondary and primary $i.e., \, 3^\circ >2^\circ >1^\circ .$