C-11-Q046mediumsingle_mcqCH4+Cl2→UV?\mathrm{CH_4 + Cl_2 \xrightarrow{UV} ?}CH4+Cl2UV?aCH3Cl+HCl\mathrm{CH_3Cl + HCl}CH3Cl+HClbCH3OH+HCl\mathrm{CH_3OH + HCl}