Arrange the compounds in increasing order of rate of reaction towards nucleophilic substitution.

1.  (i) < (ii) < (iii) 

2.  (ii) < (i) < (iii) 

3.  (iii) < (ii) < (i) 

4.  (i) < (iii) < (ii) 

Presence of electron releasing group at otho and para position wrt. to chlorine

decreases the rate of nucleophilic substitution reaction. Compound (ji) has two

electron releasing groups and compound (i) has one electron releasing group w.r.t.

chlorine while compound (i) has no electron releasing group.

So, the rate of nucleophilic substitution reaction is highest in compound (i) and order is

(iii) < (ii) <(i).