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

The $C-O$ bond length in $CO$,$CO_2$ and $CO_3^{2-}$ follows the order.

Draw the Lewis structure of $NO_2^-$.

In $O_{2}$ and $H_{2}O_{2}$,the $O-O$ bond lengths are $1.21 \mathring{A}$ and $1.48 \mathring{A}$ respectively. In ozone $(O_{3})$,the average $O-O$ bond length is

How many resonance forms can be written for the nitrate ion,$(NO_3^-)$?

Resonance structures of propenal are given below. Which of these resonating structures is more stable? Give reason for your answer.
$CH_2=CH-CH=O$ $(I)$ $\leftrightarrow$ $\stackrel{+}{CH_2}-CH=CH-\stackrel{-}{O}$ $(II)$