The decreasing order of strength of the bases, `OH^(-), NH_(2)^(-), H-C-=C^(-)` and `CH_(3)-CH_(2)^(-)`:

Options

A. `CH_(3)CH_(2)^(-)gt NH_(2)^(-) gt HC -= C^(-) gt OH^(-)`
B. `HC-=C^(-) gt CH_(3)CH_(2)^(-) gt HC -=C^(-) gt OH^(-)`
C. `OH^(-) gt NH_(2)^(-) gt HC-=C^(-) gt CH_(3)CH_(2)^(-)`
D. `NH_(2)^(-)gt HC -=C^(to)OH^(-) gt CH_(3)CH_(2)^(-)`

Answer

A

Explanation

Corresponding conjugate Lewis acids are `H_(2)O, NH_(3), HC-=CH,CH_(3)CH_(3)`
Increasing order of acid strength of these Lewis acids is
`CH_(3)CH_(3) lt NH_(3) lt HC-=CH lt H_(2)O`
Stronger an acid, weaker is its conjugate Lewis base. Therefore, decreasing order of base strength of conjugate bases as
`CH_(3)CH_(2)^(-) gt NH_(2)^(-) gt HC-=C^(-)gt OH^(-)`