In what sense is acetylene a protonic acid?

Question

Explain why its reaction with ammoniacal cuprous chloride and silver nitrate are considered as reactions of an acid?

Answer 1

Acetylene, C2H2, is a highly reactive, commercially important hydrocarbon. Its reactivity is related to its triple bond between carbon atoms and, as a consequence, its high positive free energy of formation. Because of its explosive nature, long distance shipping or pressurized storage is not recommended. Thus acetylene is generally used as it is produced without shipping or storage.

Finely divided copper in contact with acetylene forms explosive acetylides. ... acidic nature of this cake can also cause skin irritation.
The hydrogen atoms in acetylene can be replaced by metallic elements to form acetylides--e.g., acetylides of silver, copper, or sodium. The acetylides of silver, copper, mercury, and gold are detonated by heat, friction, or shock. In addition to its reactive hydrogen atom, the carbon-carbon triple bond can readily add halogens, halogen acids, hydrogen cyanide, alcohols, amines,and amides. Acetylene can also add to itself or to aldehydes and ketones. Many of the reactions mentioned here are used for the commercial manufacture of various industrial and consumer
products, such as acetaldehyde, the synthetic rubber neoprene, water-base paints, vinyl fabric and floor coverings, dry-cleaning solvents, and aerosol insecticide sprays. Acetylene is produced by any of three methods: by reaction of water with calcium carbide, by passage of a hydrocarbon through an electric arc, or by partial combustion of methane with air or oxygen

Answer 2

C2H2 loses a couple of protons in each case to form a salt:
C2H2 + 2Ag+ -----> Ag2C2 + 2H+

The same is true for Cu+.

The compounds formed are touch-sensitive explosives.

Answer 3

Because it creates a carbocation in the process.