Acetylenic hydrogens are acidic because

sigma electron density of C - H bond in acetylene is nearer to carbon, which has \( 50 \% \) \( s \)-character

acetylene has only open hydrogen in each carbon

acetylene contains least number of hydrogens among the possible hydrocarbons having two carbons

acetylene belongs to the class of alkynes with molecular formula, \( \mathrm{C}_{n} \mathrm{H}_{2 n-2} \).