(couleur) grey (Grande-Bretagne) , gray (USA) il fait gris it's a dull day, it's a grey day. faire grise mine to look morose. faire grise mine Ã  qn to give sb a cool reception.
In electrophilic aromatic substitution, the benzene ring acts as an electron donor (Lewis base or nucleophile) and reacts with an electron acceptor (Lewis acid or electrophile). The result of electrophilic aromatic substitution reactions is that an aromatic hydrogen is replaced by some other atom or functional group.
Addition reactions In the presence of ultraviolet light (but without a catalyst present), hot benzene will also undergo an addition reaction with chlorine or bromine. The ring delocalisation is permanently broken and a chlorine or bromine atom adds on to each carbon atom.ubstitution into the methyl group If chlorine or bromine react with boiling methylbenzene in the absence of a catalyst but in the presence of UV light, substitution happens in the methyl group rather than the ring. For example, with chlorine (bromine would be similar): The organic product is (chloromethyl)benzene.