The speed of chemical reactions among various substances with different functional groups depends on the type of reaction and the nature of the substituents. For aromatic substitution, electron-donating groups like OH and NH2 significantly enhance the reaction rate, while electron-withdrawing groups like NO2 slow it down. In nucleophilic substitution reactions, the stability of the leaving group is crucial; poor leaving groups like OH result in slower reactions, while excellent leaving groups like SO4H and water facilitate faster reactions. When considering compounds like OH-R-COOH or O2N-R-COOH, the specific reaction type must be clarified to determine the influencing factors on reaction speed.
