Question: is imidazole an acid or base?
Answer: Structure and properties Imidazole is amphoteric. That is, it can function as both an acid and as a base. As an acid, the pKa of imidazole is 14.5, making it less acidic than carboxylic acids, phenols, and imides, but slightly more acidic than alcohols. The acidic proton is the one bound to nitrogen.