When dry hydrogen chloride is bubbled into dry dicyclopentadiene at 60-70'practically no addition of the hydrogen chloride to the double bonds of the hydrocarbon occurs. However, if a small amount of water is present, addition of the hydrogen chloride takes place readily to form a monohydrochloride. This reaction product still contains one double bond even though an excess of hydrogen chloride be used. The chlorine atom in the dicyclopentadiene ...