How are terminal alkynes distinguished and separated from internal alkynes?

Explanation

Terminal alkynes (e.g., but-1-yne) have acidic H atom and give insoluble white precipitate of silver alkynide with alcoholic solution of `AgNO_3` and `NH_3`, whereas internal alkynes (e.g., but-2-yne) have no acidic H atom and do not react to give a precipitate.
The precipitate obtained with terminal alkyne is filtered, leaving the easily recoverable unreacted internal alkyne (but-2-yne) in the solution. The terminal alkyne (but-1-yne) is regenerated by treating the silver alkynide with HCl.