Nucleophilic substitution (SN1): A type of chemical reaction where a nucleophile replaces a leaving group in a substrate molecule, often proceeding via a unimolecular mechanism involving the formation of a carbocation intermediate.
Carbocation:A positively charged ion (cation) in which one of the carbon atoms has an incomplete octet and bears the positive charge, crucial in many organic reactions including SN1 processes.
Rate: determining step - The slowest step in a reaction mechanism that determines the overall rate at which the reaction proceeds; in SN1 reactions, this is typically the formation of the carbocation intermediate