(N/A) large number of alkyne molecules combine with each other to form a giant molecule,which is called the polymerization of alkynes.
There are mainly two types of alkyne polymerization: linear polymerization and cyclic polymerization.
$(a)$ Linear polymerization of alkynes: Under suitable conditions,linear polymerization of ethyne takes place to produce polyacetylene or polyethyne,which is a high molecular weight polyene containing repeating units of $[CH=CH-CH=CH]$ and can be represented as $+CH=CH-CH=CH-_{n}$. Under special conditions,this polymer conducts electricity. Thin films of polyacetylene can be used as electrodes in batteries. These films are good conductors,lighter,and cheaper than metal conductors.
$(b)$ Cyclic polymerization: Ethyne,upon passing through a red-hot iron tube at $873 \ K$,undergoes cyclic polymerization. Three molecules polymerize to form benzene,which is the starting molecule for the preparation of derivatives of benzene,dyes,drugs,and a large number of other organic compounds. This is the best route for converting aliphatic to aromatic compounds.