The correct order of increasing basicity of the given conjugate bases `(R=CH_(3))` is

Options

A. `RCObar(O) lt HC-=bar(C ) lt bar(R ) lt bar(N)H_(2)`
B. `bar(R ) lt HC-=bar(C ) lt RCObar(O) lt bar(N)H_(2)`
C. `RCObar(O) lt bar(N)H_(2) lt HC-=bar(C ) lt bar(R)`
D. `RCObar(O) lt HC-=bar(C ) lt bar(N)H_(2) lt bar(R)`

Answer

D

Explanation

In carboxylate ion, the negative charge is present on oxygen, a most electronegative element here, thus it is resonance stabilised. `HC-=C^(-)`: Carbon is `sp` hybridized so its electronegativity is increased higher relative to nitrogen. `bar(N)H_(2)`: Nitrogen is more electronegative than `sp^(3)` hybridised `C`-atom. form the above discussion. it is clear that the order of the stability of conjugate bases is as `RCObar(O) gt HC-=C^(-)bar(N)H_(2) gt R^(-)` and higher is the stability of conjugate bases, lower will be basic character. hence, the order of basic character is as `RCObar(O) lt HC-=C^(-)bar(N)H_(2) lt R^(-)`