Which one of the following is more acidic ?

Options

A. Butane
B. 1-butene
C. 1-butyne
D. 2-butyne

Answer

C

Explanation

`Hunderset(sp) (C ) -= underset(sp) (C ) - underset(sp^(3)) ( C) H_(2) - underset(sp^3) ( C) H_(3)` but-1-yne
`H_(3) underset(sp^3) ( C)- underset(sp) (C ) -= underset(sp) ( C) - underset(sp^3) ( C) H_(3)` but-2-yne
In but-1-yne, one hydrogen is attached to sp hybridized carbon (sp-s overlap). s -character increases the acidity, so 1-butyne is most acidic