Which one is the correct order of acidity?

Options

A. `CH_(2) = CH_(2) gt CH_(3)-CH = CH_(2) gt CH_(3) - C -= CH gt CH -= CH`
B. `CH -= CH gt CH_(3) - C -= CH gt CH_(2) = CH_(2) gt CH_(3)-CH_(3)`
C. `CH-=CH gt CH_(2)=CH_2 gt CH_3 - C-= CH gt CH_(3) - CH_(3)`
D. `CH_(3)-CH_(3) gt CH_(2) = CH_(2) gt CH_(3)- C -= CH gt CH -= CH`

Answer

B

Explanation

Concept : More will be the s-character, more will be the electronegativity.
sp `rArr` s - character 50%
`sp^2 rArr` s - character 33.3 %
`sp^3 rArr` s- character 25%
Alkynes more acidic than alkenes which are further more acidic than alkanes due to the different electro negativity of , sp `sp^2` and `sp^3` hybrid carbon (order of electro negativity `= C_(sp) gt C_(sp^2) gt C_(sp^3))+I` effect decreases the acidic strength of alkynes so the overall order of acidic strength will be
`CH -= CH gt CH_3 - C -= CH gt CH_2 = CH_2 gt CH_3 - CH_3`