In the questions, arrange the compounds in increasing order of the rate of reaction towards nucleophilic substitution.
(i) (c) < (b) < (a)
(ii) (b) < (c) < (a)
(iii) (a) < (c) < (b)
(iv) (a) < (b) < (c)
(iv) The reactivity of aryl halides increases with the increase in electron-withdrawing group. Therefore, the more the number of electron-withdrawing groups, the more the rate of nucleophilic substitution.