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

What is the $O-O$ bond length in the ozone $(O_3)$ molecule (in $\text{ pm}$)?

Which of the following pairs of structures does not represent resonating structures?

Draw the resonance structures for the following compounds. Show the electron shift using curved-arrow notation.
$(a)$ $C_{6}H_{5}OH$
$(b)$ $C_{6}H_{5}NO_{2}$
$(c)$ $CH_{3}CH=CH-CHO$
$(d)$ $C_{6}H_{5}CHO$
$(e)$ $C_{6}H_{5}CH_{2}^{+}$
$(f)$ $CH_{3}CH=CH-CH_{2}^{+}$

$CH_2 = O \leftrightarrow \overset{\oplus}{C}H_2 - \overset{\ominus}{O} \leftrightarrow \overset{\ominus}{C}H_2 - \overset{\oplus}{O}$
Which of these structures is practically not a valid canonical structure for formaldehyde?

Explain the structure of $CO_{2}$ molecule.