Resonance structures of a molecule do not have:

What is the correct increasing order of $C-O$ bond length in $CO$,$CO_3^{2-}$,and $CO_2$?

$p-$nitro$-N, N-$dimethylaniline cannot be represented by which of the following resonating structures? (Refer to the provided structures $I, II, III, IV$)

Which of the following compounds will not exist as a resonance hybrid? Give a reason for your answer.
$(a)$ $CH_3OH$
$(b)$ $RCONH_2$
$(c)$ $CH_3CH=CHCH_2NH_2$

What is the number of Lewis structures for $NO_2^{-}$?

Identify the relationship between the following two structures: $\begin{matrix} \overset{\Theta}{\overset{\centerdot \,\centerdot}{C}}H_2-C(=O)-CH_3 \end{matrix}$ and $\begin{matrix} CH_2=C(O^{\Theta})CH_3 \end{matrix}$