Counterexamples: Methane is a saturated hydrocarbon and has four hydrogens bonded to its carbon. Ethyne, formerly known as acetylene, is an unsaturated hydrocarbon, and has just one hydrogen on each carbon, as has the aromatic compound benzene. Naphthalene has less than one hydrogen per carbon. Isobutane, or 2-methyl-propane, is a fairly common branched saturated hydrocarbon.