Question

Select the number of species having bond with fractional bond order (Indicated bond)
$N_{3}^{-},CO_{3}^{2 -},ClO_{3},ClO_{3}^{-},O_{3},CO_{2},BF_{3},Al_{2}Cl_{6},CH_{3}COOH$ ( $C-O$ bond)

Answer 1

Molecule or ions that have resonance structure i.e. fractional bond order is possible $CO_{3}^{2 -},ClO_{3}^{-},O_{3},BF_{3},CH_{3}COOH$ ( $C-O$ bond)
Fractional bond order
$N_{3}^{-}$

$CO_{3}^{2 -}$

$B.O.=\frac{4}{3}=1.33$
$ClO_{3}$

$B.O.=2$
$ClO_{3}^{-}$

$B.O.=\frac{5}{3}=1.66$
$O_{3}$

$B.O.=\frac{3}{2}=1.5$
$CO_{2}$
$O=C=O$
$B.O.=2$
$BF_{3}$

$B.O=1.33$
$Al_{2}Cl_{6}$

$B.O.=1$
$CH_{3}COOH$ ( $C-O$ bond)