Bond strengths in CFCs drive ozone depletion

Steps:

• CFCs reach stratosphere and absorb UV light, causing bond breakage.
• Homolytic fission releases Cl• radicals, which attack O3.
• Bond dissociation energy (BDE) determines fission ease: lower BDE means weaker bond.
• C-Cl BDE (351 kJ/mol) is less than C-F BDE (485 kJ/mol), favoring C-Cl fission.

Why B is correct:

• C-Cl bonds have lower BDE than C-F bonds, so they undergo homolytic fission more readily under UV radiation, releasing chlorine for ozone catalysis.

Why the others are wrong:

• A: Identical to B, but question implies selection of distinct correct statement; A may be distractor.
• C: CH3Cl (BP -24°C) is less volatile than CH4 (BP -161°C) due to higher molecular weight and polarity.

Not enough information for D.

Final answer: B