Linked from
The 14 pages that link to Acid catalysis, each with the reason it gives.
EsterRelated: Protonation activates the carbonyl during Fischer esterification.
AcidRelated: Proton donation or electron-pair acceptance can make reactants more reactive.
HydroniumRelated: Hydronium can protonate reactants and lower reaction barriers in water.
EnolRelated: Protonation of the carbonyl oxygen enables acid-catalyzed enol formation.
Urea-formaldehyde resinRelated: Acidic conditions commonly speed the resin’s condensation and cure.