question_answer

Arrange the following halides in order of increasing \[{{S}_{N}}2\] reactivity : \[C{{H}_{3}}Cl,\,C{{H}_{3}}Br,\,C{{H}_{3}}C{{H}_{2}}Cl,\]\[{{(C{{H}_{3}})}_{2}}CHCl\].

Answer:

                As the size of the alkyl group increases, \[{{S}_{N}}2\] reactivity decreases. Further, \[C-Br\] bond being weaker is easier to break than \[C-Cl\] bond. Therefore, the overall increasing \[{{S}_{N}}2\] reactivity follows the order : \[{{(C{{H}_{3}})}_{2}}CHCl<C{{H}_{3}}C{{H}_{2}}Cl<C{{H}_{3}}Cl<C{{H}_{3}}Br.\]