alkenes	aliphatic hydrocarbons
alkynes	aromatic hydrocarbons
all neutral oxygen containing compounds
easily sulfonated aromatics (2 or more alkyl groups)

Notes:

1. Water insoluble compounds containing carbon, hydrogen, and oxygen are soluble.



2. If the compound is unsaturated, is readily sulfonated, or possesses a functional group containing oxygen, it will dissolve.



3. Many 2^o & 3^o alcohols are dehydrated (to form olefins) and polymerize. This polymer is usually black and insoluble in sulfuric acid. This does not mean that the original compound did not dissolve in sulfuric acid.