Question

Arrange the following alkyl halides in order of dehydrohalogenation:

$C_{2}H_{5}I,C_{2}H_{5}Cl,C_{2}H_{5}Br,C_{2}H_{5}F$

• A. $C_{2}H_{5}F > C_{2}H_{5}Cl > C_{2}H_{5}Br > C_{2}H_{5}I$
• B. $C_{2}H_{5}I > C_{2}H_{5}Br > C_{2}H_{5}Cl > C_{2}H_{5}F$
• C. $C_{2}H_{5}I > C_{2}H_{5}Cl > C_{2}H_{5}Br > C_{2}H_{5}F$
• D. $C_{2}H_{5}F > C_{2}H_{5}I > C_{2}H_{5}Br > C_{2}H_{5}Cl$

Answer 1

Answer: (B)

$C_{2}H_{5}I > C_{2}H_{5}Br > C_{2}H_{5}Cl > C_{2}H_{5}F$

Answer 2

The reactivity order can be explained on the basis of C-X bond strength. Lower the bond strength, higher is the reactivity.