Among the following,the least stable resonance structure is

What is the $O-O$ bond length in the resonance hybrid of ozone (in $pm$)?

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

The formal charge on the $O$ atom and the $P-O$ bond order in the $PO_4^{3-}$ ion are,respectively,.......

In the resonance structure of nitrobenzene,what is the total partial positive charge $(\delta+)$ on the ring?

The increasing order of stability of the resonance structures is: