Strongly corrosive, dense, oily liquid. Very reactive, dissolves most metals; concentrated acid oxidizes, dehydrates, or sulfonates most organic compounds. Hazard: Strong irritant to tissue. Use great caution in mixing with water because of heat evolution that causes explosive spattering. Always add the acid to the water, never the reverse. Uses: An alkylation catalyst, electroplating baths, iron and steel, lab reagent, non ferrous metallurgy.