Alkynes are more reactive than usual hydrocarbons. For example, they are more reactive than alkenes in many reactions. If the alkyne is at the end of a molecule, it is easy to remove the proton with a strong base. Then, the alkyne can be used in addition reactions. For example, it can be added to a ketone. Alkynes are also easy to reduce to double bonds. They can be made into both "trans" and "cis" double bonds. Alkynes are also used a lot in pericyclic reactions.