text: Cold, concentrated sulfuric acid is used with neutral, water-insoluble compoinds containing no elements other than carbon, hydrogen, and oxygen.  If the compound is unsaturated, is readily sulfonated, or possesses a functional group containing oxygen, it will dissolve in cold concentrated sulfuric acid.  This is frequently accompanied by a reaction such as sulfonation, polymerization, dehydration, or addition of the sulfuric acid to olefinic or acetylenic linkages.  In many cases, however, the solute may be covered by dilution with ice water.