Question

The rate of dehydrohalogenation of which one among the following is less?

• A. $CH _{3} CH _{2} CH _{2} Br$
• B. $CH _{3} CH _{2} CH _{2} Cl$
• C. $Cl _{3} I _{3} Cl _{2} Cl H _{2}$
• D. $CH_3-\underset{\overset{|}{C}H_3}{C}H-CH_2l$

Answer 1

Answer: (B)

Dehydrohalogenation reaction order is alkyl halide relative reactivity order is $3^{\circ}>2^{\circ}>1^{\circ}$ Alkyl halide reactivity order is $I > Br > Cl > F$ (in $\beta$ elimination of $F$ is rarely used).

When heated with strong base, alkyl halides typically undergo a 1,2 -elimination reaction to generate alkenes.