The university's method is to add silver ammonia solution, that is, silver hydroxide and acetylene react and heat to generate silver acetylene precipitate, then potassium permanganate is added to fade ethylene, and the rest is cyclohexane. The high and middle school method can burn to see whether the smoke is thick or not, followed by ethylene, and finally cyclohexane, and can also be determined by the amount of hydrogen consumed by addition! Acetylene 1mol is more, and 2mol of hydrogen can be added, followed by ethylene 1mol, and 1mol can be added, but cyclohexane cannot be added.