Differences between saturated and unsaturated hydrocarbons

Saturated hydrocarbons (alkanes) will burn (undergo combustion) they are generally unreactive to most reagents. They will undergo a substitution reaction with halogens, but only if exposed to ultraviolet light. Unsaturated hydrocarbons, alkenes and alkynes, not only burn, but also react by addition of reagents to the double or triple bonds.