The Free-Radical Chain Reaction Initiation generates a radical intermediate. Propagation:The intermediate reacts with a stable molecule to produce another reactive intermediate(and a product molecule). Termination:Side reactions that destroy the reactive intermediate. Chapter 4 4 Chapter 4 4 The Free-Radical Chain Reaction • Initiation generates a radical intermediate. • Propagation: The intermediate reacts with a stable molecule to produce another reactive intermediate (and a product molecule). • Termination: Side reactions that destroy the reactive intermediate