Răspuns:
CH4 + Br2 = CH3-Br + HBrCH4 + 2 Br2 = CH2Br2 + 2 HBrCH4 + 3 Br3 = CHBr3 + 3 HBrCH4 + 4 Br2 = CBr4 + 4 HBr