A group which deactivates the benzene ring towards electrophilic substitution but which directs the incoming…
A group which deactivates the benzene ring towards electrophilic substitution but which directs the incoming group principally to the o- and p-positions is
$-\mathrm{NH}_{2}$
$-\mathrm{Cl}$
$-\mathrm{NO}_{2}$
$-\mathrm{C}_{2} \mathrm{H}_{5}$
Solution
$-\mathrm{Cl}$ group is o-, p-directing due to $+\mathrm{R}$ effect; however it is deactivating due to strong $-\mathrm{I}$ effect of $\mathrm{Cl}$ (difference from other o-, $\mathrm{p}$ -directing groups which are activating). The net result is that chlorobenzene undergoes o-, p-substitution, but with difficulty.
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