(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.
4. Substituents with pi bonds to electronegative atoms (e.g. -C=O, -NO 2) adjacent to the pi system are electron withdrawing groups (EWG) - they deactivate the aromatic ring by decreasing the electron density on the ring through a resonance withdrawing effect.