The sulfonation of ethylbenzene is an electrophilic aromatic substitution reaction. When ethylbenzene is sulfonated at 0°C and at 100°C, the following ratios of substitution products are observed:
At 0°C: para (55%), ortho (40%)
At 100°C: para (70%), ortho (20%)
(a) Why do the product ratios change when the temperature increases?
(b) Predict what would happen if the product mixture from the reaction at 0°C was heated to 100°C in the presence of a sulfonating agent. Remember that sulfonation is reversible, unlike other electrophilic aromatic substitution reactions.