Why alkynes are more acidic than alkenes and alkanes ?

Explanation

Alkynes are weakly acidic in nature whereas alkenes and alkanes do not show any acidic character. It can be explained as carbon atoms of alkynes, alkenes and alkanies and are sp, `sp^2` and `sp^3` hybridised respectively. Due to greater s character in alkynas (50%), the electrons are more tightly held by the nucleus than alkenes (33%) and alkanes (25%).Consequently, the electron pair of `H-C -=` bond gets displaced more towards the carbon atom and the release of `H^(+)` ion becomes more easier than alkenes and alkanes. Hence, we can say that the more the s-character, the more will be the acidic strength. The acidic character decreases as follows:
`HC -= CH gt CH_2 = CH_2 gt CH_3 - CH_3`