Correct Answer - `H-C-=C-H>C_(6)H_(6)>C_(6)H_(14)`. Due to maximum s orbital character in enthyne (50 per cent)as compared to 33 per cent in benzene and 25 per cent in n-hexane.
Acidic character of a species is defined on the basis of ease with which it can lose its H– atoms. The hybridization state of carbon in the given compound is:
As the s–character increases, the electronegativity of carbon increases and the electrons of C–H bond pair lie closer to the carbon atom. As a result, partial positive charge of H– atom increases and H+ ions are set free. The s–character increases in the order: `sp^3 lt sp^2 lt sp` Hence, the decreasing order of acidic behaviour is Ethyne gt Benzene gt Hexane.
