Which structure has delocalised $\pi$-electrons?

$H_3PO_3$ can be represented by structures $(1)$ and $(2)$ shown below. Can these two structures be taken as the canonical forms of the resonance hybrid representing $H_3PO_3$? If not,give reasons for the same.

Explain the structure of $CO_{3}^{2-}$ ion in terms of resonance.

The bond order of individual carbon-carbon bonds in benzene is

Taking into account hybridization and resonance effects,rank the following $C-O$ bonds in order of decreasing bond length. The structure provided is the carbonate ion $(CO_3^{2-})$.

Which of the following pairs of canonical forms contribute equally to the resonance hybrid?