See image — Hydrocarbons Chemistry Question

💡 Solution & Explanation

Concept: Radical chain reactions proceed through three types of steps: initiation (generation of radicals from non-radical species), propagation (radicals react with molecules to produce new radicals, continuing the chain), and termination (two radicals combine to give a non-radical product). Heterolytic cleavage is an ionic mechanism, not radical. Reasoning: In the given reaction, a bromine radical (Br•) reacts with the alkene (CH3)2C=CH2. The bromine radical adds to the terminal carbon (CH2) of the double bond, breaking the pi bond homolytically. This produces a new carbon radical (CH3)2C•-CH2Br. The key observation is that a radical (Br•) is consumed and a new radical ((CH3)2C•) is generated. The chain is therefore continued — one radical is replaced by another. This is the definition of a propagation step. Why other options fail: (a) Initiation involves breaking a non-radical molecule into radicals (e.g., Br2 → 2Br•), which is not happening here. (b) Termination involves two radicals combining to give a stable non-radical product, which is not happening here. (d) Heterolytic cleavage involves ionic bond breaking (both electrons go to one atom), which does not apply to radical reactions. Therefore, the correct answer is C.