Q.How will you distinguish 1-butyne and 2-butyne?

Step 1. 1-Butyne, CH3-CH2-C$\equiv$C-H, is a TERMINAL alkyne -- it has a hydrogen directly on a triple-bonded carbon, which is weakly acidic (owing to the high s-character of the sp carbon holding that C-H bond).

Step 2. 2-Butyne, CH3-C$\equiv$C-CH3, is an INTERNAL alkyne -- both triple-bonded carbons carry a methyl group instead of a hydrogen, so it has NO acidic (terminal) hydrogen at all.

Step 3. Treating each with ammoniacal silver nitrate (AgNO3/NH4OH): 1-butyne's acidic terminal H is removed by the mildly basic ammoniacal solution, and the resulting acetylide anion precipitates as silver butynide (a pale/whitish solid); 2-butyne, having no such H to lose, shows NO reaction and NO precipitate.

Step 4. The same distinction works with ammoniacal cuprous chloride (Cu2Cl2/NH4OH): 1-butyne gives a precipitate of copper butynide (typically reddish); 2-butyne again gives no precipitate. …

Check first whether each alkyne is TERMINAL (a triple-bond H present, hence acidic and reactive with ammoniacal Ag+/Cu+) or INTERNAL (no triple-bond H, hence unreact …

• Assuming both alkynes will react with ammoniacal AgNO3/Cu2Cl2 simply because both are alkynes -- the test specifically distinguishes TERMINAL from INTERNAL alkyne …