Alkenes such as ethylene, there are very reactive. They will easily react with some other atom or compound to form a new one that satisfies all valences. For the reason, these two are the most popular basic building block in the petrochemical industry. They react easily themselves and other petrochemicals. But triple bonds such as Acetylene are so much more reactive, even explosive, than ethylene that most petrochemical companies shy away from using it because of its hazardous behavior.