Question

Base strength of
(i) `CH_3CH_2^(-)`
(ii) `CH_2=CH^(-)`
(iii) `CH-=C^(-)`
A. `(iii)gt(ii)gt(i)`
B. `(i)gt(iii)gt(ii)`
C. `(i)gt(ii)gt(iii)`
D. `(ii)gt(i)gt(iii)`

Answer 1

Correct Answer - C
The order of relative basicity is the reverse of the order of relative acidity of the corresponding conjugate acids: Relative acidity: `HC-=CHgtCH_2=CH_2gtCH_3CH_3`. This is on account of the fact that sp hybrid C of ethene has maximum electronegativity while `sp^(3)` hybrid C of ethane has minimum electronegativity.
Relative basicity: `HC-=overlineC:ltCH_2=overline(C)HltCH_3overline(C)H_2`