Q. Which of the following is the correct order of reactivity of haloalkanes towards nucleophilic substitution? (2021)
A.R-I > R-Br > R-Cl > R-F
B.R-F > R-Cl > R-Br > R-I
C.R-Cl > R-Br > R-I > R-F
D.R-Br > R-I > R-Cl > R-F
Solution
The reactivity of haloalkanes towards nucleophilic substitution is primarily determined by the bond strength of the carbon-halogen bond. Iodine has the weakest bond, making R-I the most reactive, followed by R-Br, R-Cl, and R-F.