Jaques d'Alltrades writes:

Eyhylene (heavy carburetted Hydrogen - C2H2) is used for ripening
tomatoes - by some producers. Acetylene is used for welding - (CH2)

Ethylene is C2H4, Acetylene C2H2, also known as Ethene and Ethyne
respectively, and the simplest forms of the Alkene and Alkyne groups
of organic chemicals. The Alkanes start one lower with Methane before
progressing to the two-carbon Ethane.

Knew the organic section of my chemistry A-Level would come in ahndy
one day.

Anthony