Acetylene and hydrogen cyanide is passed through a red hot tube 2:1 to form _________.
Acetylene ( ) on passing through a red-hot iron tube at undergoes cyclic polymerization. Three molecules of acetylene undergo polymerization to produce benzene .
This is Diels Alder reaction: The Diels-Alder reaction is a conjugate addition reaction of a conjugated diene to an alkene or alkyne (the dienophile) to produce cyclohexane.
Diels Alder reaction
Thus, Acetylene and hydrogen cyanide is passed through a red hot tube 2:1 to form benzene.