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

Explanation

`O_(N)-CH_(2)-CH_(2)-overset(Theta)(O)ion` is more stable than `CH_(3)-CH_(2)-overset(Theta)(O)` as - I effect of the `-NO_(2)` group causes dispersal of - ve charge on the O - atom. On the other hand, `-CH_(2)CH_(3)` group has +I effect which tends to intensity the - ve charge on the O - atom leading to destabilisation of the ion.