Question

Which of the following statements are correct about \[\ce{CO^{2-}3}\]?

(i) The hybridisation of central atom is sp³.

(ii) Its resonance structure has one \[\ce{C - O}\] single bond and two \[\ce{C = O}\] double bonds.

(iii) The average formal charge on each oxygen atom is 0.67 units.

(iv) All \[\ce{C - O}\] bond lengths are equal.

Answer 1

(iii) The average formal charge on each oxygen atom is 0.67 units.

(iv) All \[\ce{C - O}\] bond lengths are equal.

Explanation:

(i) The hybridization of the central carbon atom in \[\ce{CO^{2-}3}\] is sp² as the carbon is bonded with three oxygen atoms. So, the given statement is incorrect.

(ii) The resonance structure of \[\ce{CO^{2-}3}\] has one \[\ce{C = O}\] double bonds and two \[\ce{C - O}\] single bonds. So, the statement is incorrect.

(iii) The net charge on three oxygen atoms is \[\ce{- 2}\], hence the average formal charge on each oxygen atom is 0.67 units. So, the given statement is correct.

(iv) As it can be seen from the resonating structures that the structures of the bonds are not fixed. Hence, all the  \[\ce{C - O}\] bond lengths are equal. So, the given statement is correct.