Chapter 14, Problem 101AP

When a mixture of methane and bromine is exposed to light, the following reaction occurs slowly:

${\text{CH}}_{\text{4}}\left(g\right){\text{ + Br}}_{\text{2}}\left(g\right)\underset{}{\to }{\text{CH}}_{\text{3}}\text{Br}\left(g\right)\text{+ HBr}\left(g\right)$

Suggest a reasonable mechanism for this reaction. (Hint: Bromine vapor is deep red: methane is colorless.)