Termination products in free-radical bromination of ethane

Steps:

• Free-radical mechanism includes initiation (Br₂ → 2Br•), propagation (forming C₂H₅Br and HBr), and termination.
• Termination step: two ethyl radicals combine (2C₂H₅• → C₄H₁₀, butane).
• Termination step: two bromine radicals combine (2Br• → Br₂, bromine).
• Hydrogen bromide forms only in propagation, not termination.

Why C is correct:

• Butane and bromine are directly formed via radical coupling in termination steps, per the mechanism definition.

Why the others are wrong:

• A includes 2, but HBr arises from propagation (C₂H₆ + Br• → C₂H₅• + HBr), not as a listed termination product.
• B includes 2 but excludes 3, ignoring Br₂ regeneration in termination.
• D includes 2 but excludes 1, overlooking butane from ethyl radical dimerization.

Final answer: C