Alkynes are significantly more acidic than other hydrocarbons, such as alkanes and alkenes, due to the sp hybridization of their carbon atoms.  The carbon-hydrogen bond in terminal alkynes is composed of an sp-hybridized carbon and an s-orbital hydrogen, which results in a higher percentage of s-character in the bond. When a hydrogen is removed from an alkyne, the resulting acetylide anion is stabilized by the sp hybridized carbon, which can effectively distribute the negative charge over the p-orbitals of the carbon.