Hydrochloric acid is one of the most corrosive of the non-oxidising acids in contact with copper alloys, and is handled in dilute solutions. Contact with metals produces hydrogen gas, which creates the chance of an explosion. It produces poisonous gas, including chlorine, in a fire. It is soluble in benzene, alcohol, and ether; it is insoluble in hydrocarbons, and incompatible or reactive with metals, hydroxides, amines, and alkalis. Hydrochloric acid's fumes have an acid, penetrating odour. Aqueous solutions of hydrochloric acid attack and corrode nearly all metals, except mercury, silver, gold, platinum, tantalum, and certain alloys. It may be coloured yellow by traces of iron, chlorine, and organic matter.Non-flammable gas.