methane ethane octane cyclohexane benzene chlorobenzene phenol benzoic acid nitrobenzene ethene propene (cis)-but-2-ene (trans)-but-2-ene bromomethane bromoethane 2-bromopropane tert-butyl bromide carbenium methanol ethanol propan-2-ol tert-butanol methanal propanone methanoic acid ethanoic acid (dimer) ammonia methylamine dimethylamine trimethylamine