Complex sentence: Acid gas or Sour gas, also sour acid gas or acid sour gas, is natural gas which contains up to 20% hydrogen sulfide contaminant by weight and the aromatic hydrocarbons benzene, toluene, mixed xylenes and ethylbenzene.
Split into simpler sentences: Acid gas or Sour gas, also sour acid gas or acid sour gas, is natural gas which contains up to 20% hydrogen sulfide contaminant by weight. It may also contain the aromatic hydrocarbons benzene, toluene, mixed xylenes and ethylbenzene.