Which of the two:

Which of the two: ${{O}{2}}$N—C${{H}{2}}$—C${{H}{2}}$${{O}^{-}}$ or C${{H}{3}}$— C${{H}_{2}}$—${{O}^{-}}$ is expected to be more stable and why?

${{O}{2}}$N—C${{H}{2}}$—C${{H}{2}}$${{O}^{-}}$ is expected to be more stable than C${{H}{3}}$— C${{H}{2}}$${{O}^{-}}$
In ${{O}
{2}}$N —<— C${{H}{2}}$—CHO, due to the I-effect exerted by —N${{O}{2}}$ group, there occurs a dispersal of s the negative charge, whereas in C${{H}{3}}$ -----»— C${{H}{2}}$${{O}^{-}}$ due to +I effect exerted by C${{H}_{3}}$, there occurs an intensification of the negative charge. Dispersal of the charge leads to more stability of the ion.