• # question_answer 71)   Which of the following statements are correct about $CO_{3}^{2-}$? (a) The hybridisation of central atom is $s{{p}^{3}}$ (b) Its resonance structure has one C-O single bond and two C = O double bonds (c) The average formal charge on each oxygen atom is -0.67 units (d) All C-O bond lengths are equal

(c, d) In$CO_{3}^{2-}$, the hybridisation of carbon atom is $s{{p}^{2}}$ and not$s{{p}^{3}}$. Its resonance structure is : i.e., the resonance structure has two C - O bonds and one C = O bond. Formal charge on double bond oxygen = 0 Formal charge on single bonded oxygen = -1 Average formal charge on oxygen = $\frac{0-1-1}{3}=-\frac{2}{3}$ = - 0.67 All C - O bond lengths are same.