Final answer:
Polar protic solvents enhance the rate of SN1 reactions by stabilizing the carbocation intermediate formed in the rate-determining step.
Step-by-step explanation:
In SN1 reactions, polar protic solvents enhance the rate of the reaction by stabilizing the carbocation intermediate formed in the rate-determining step. These solvents have both polar and protic characteristics, meaning they can form hydrogen bonds with the carbocation, increasing its stability. The solvent molecules surround and solvate the carbocation, reducing its reactivity towards the nucleophile and promoting the formation of the substitution product.