Suggest the name of a Lewis acid other than anhydrous aluminium chloride which can be used during ethylation of benzene.
Classify the following groups as activating or deactivating with respect to further electrophilic substitution of aromatic ring:
(a) – Cl (b) -CN
(c) – NH2 (d) –SO3H
(e) –NO2 (f) – CH3.