For the question that follow, consider the best lewis structures of the following oxyanions:
(i) no2 -
(ii) no3 -
(iii) so3 2-
(iv) so4 2-
(v) bro3 -
in which of the ions do all x-o bonds (x indicates the central atom) have the same length?

(i) NO₂⁻

(ii) NO₃⁻

(iv) SO₄²⁻

(v) BrO₃⁻

Explanation:

The conjugation of π electrons in the selected oxyanions create resonance structures wich lead to equal X-O bond lenghts. The resulting bond lenght will be an average of single and double bond lenghts in the ion. Spectroscopic analysis can be used to prove this assumption.

The figure attached shows one lewis structure for each oxyanion.

- lead + phosphoric acid = hydrogen + lead(ii) phosphate