Step 1: Same as SN1 — carbocation formation (RDS) Step 2: Base (often solvent) removes a beta-H from the carbocation → alkene

Always accompanies SN1: Cannot have E1 without SN1 competing (both share the same carbocation intermediate). SN1 product = substitution; E1 product = elimination.

Higher temperature favors E1 over SN1: Entropy drives elimination (2 product molecules from 1 reactant).

Zaitsev product: More substituted alkene is major (thermodynamic control — base removes beta-H that gives the most stable alkene).