Termination Step in Free Radical Chlorination

Steps:

• UV light initiates Cl2 dissociation into Cl• radicals.
• Propagation: Cl• abstracts H from CHCl3, forming HCl and •CCl3 radical.
• •CCl3 reacts with Cl2 to form CCl4 and regenerate Cl•.
• Termination occurs when radicals combine, such as •CCl3 + Cl• → CCl4 (CHCl3Cl).

Why C is correct:

• In radical reactions, termination involves two radicals combining without generating new radicals, as in •CCl3 + Cl• → CHCl3Cl (CCl4).

Why the others are wrong:

• A: HCl forms in propagation via H abstraction.
• B: CH3Cl is unrelated; no methyl groups present.
• D: H atom is not produced; only Cl• and •CCl3 radicals form.

Final answer: C