Which of the two: `O_(2)NCH_(2)CH_(2)O^(–)` or `CH_(3)CH_(2)O^(–)` is expected to be more stable and why ?

Explanation

`O_2 NCH_2 CH_2 O^(-)` is more stable than `CH_3 CH_2 O^(-)` . This is because `-NO_2` group is electron attracting and exerts -l -effect. Therefore, negative charge present on-`O^(-) `- is dispersed and molecule is stabilised. On the other hand, `-CH_3 -CH_2` - group in `CH_3 CH_2 O^(-)` exerts +l-effect and increases electron density at -`O^(-)` . This destabilises the `CH_3 -CH_2O^(-)` species.