Question

Among the species `CO_2, CO_3^(2-), CH_3COO^(-)`, CO, HCHO which has longest carbon-oxygen bond
A. `CO_2`
B. `CH_3COO^-`
C. CO
D. `CO_3^(2-)`

Answer 1

Correct Answer - D
CO, is a resonance hybrid of following three structures :
CO is Mainly a resonance hybrid of following two structures :
`: overset(-)(C)-=O :^(+)harr : C=overset(ddot)(O : )`

`H-oversetoverset(H)(|)C=O` does not show resonance.
With more single bond character in resonance hybrid of `CO_3^(2-), C-O` bond length is longest.