Comparison of Substitution and Elimination reactions

Substitution v/s Elimination

Elimination Reactions (EI)

Orientation in Elimination Reaction

When haloalkanes with beta -hydrogen atom are boiled with alcoholic solution of KOH, they undergo elimination of hyarogen halide resulting in the formation of alkenes. These reactions are called beta -elimination reactions or dehydrohalogenation reactions. These reactions follow Saytzeff's rule. Substitution and elimination reactions often compete with each other. Mostly bases behave as nucleophiles and therefore can engage in substitution or elimination reactions depending upon the alkyl halide and the reaction conditions. In the elimination reactions, the reactivity of alkyl halides follow the sequence