Which of the following aromatic rings IS alkylated most rapidly by chloroethane/AlCI3? benzene ethylbenzene bromobenzene benzenesulfonic acid nitrobenzene Solution ethylbenzene is alkylated most rapidly due to the presence of electron donating group. Explanation: ethyl group on benzene ring is an electron donating group and increases the electron density on benzene ring. so the electrophilic aromatic substitution occurs more rapidly..