Polar protic solvents are typically used in SN₁ (unimolecular nucleophilic substitution) reactions. These solvents, such as water, alcohols, or carboxylic acids, possess a hydrogen atom connected to an electronegative atom (e.g., O or N). In SN₁ reactions, the leaving group departs first, forming a carbocation intermediate. Polar protic solvents stabilize the carbocation through solvation, promoting ion-dipole interactions. Additionally, these solvents facilitate the nucleophilic attack in the subsequent step. The choice of solvent influences reaction rates and product distributions in SN₁ reactions, and polar protic solvents are well-suited for promoting these reactions.