A heavy, corrosive, oily liquid, H2SO4, colorless when pure, but usually yellowish or brownish, produced by the combined action of sulfur dioxide, oxygen (from the air), steam, and nitric fumes. It attacks and dissolves many metals and other intractable substances, sets free most acids from their salts, and is used in the manufacture of hydrochloric and nitric acids, of soda, of bleaching powders, etc. It is also powerful dehydrating agent, having a strong affinity for water, and eating and corroding paper, wood, clothing, etc. It is thus used in the manufacture of ether, of imitation parchment, and of nitroglycerin. Sulphuric acid is one of only 6 strong acids, acids that dissociate 100% in water.