Free radical substitution of methane

Steps:

• Identify the balanced equation: Cl₂ + CH₄ → CH₃Cl + HCl.
• Confirm products: substitution yields CH₃Cl and HCl, not H₂.
• Recall conditions: requires gaseous reactants and UV light for initiation.
• Match option with correct equation and conditions.

Why C is correct:

• Matches the free radical mechanism where UV light generates Cl• radicals, leading to CH₃Cl + HCl as per the substitution reaction formula.

Why the others are wrong:

• A: Produces H₂ instead of HCl, violating the substitution product.
• B: Produces H₂ instead of HCl and uses aqueous conditions, which do not support free radical initiation.
• D: Uses aqueous chlorine, which prevents the gas-phase UV-driven reaction.

Final answer: C