Question

The correct order of increasing $C-O$ bond lengths in $CO$, $C{O}_3^{2-}$ and $C{O}_2$ is:

• A. $C{O}_3^{2-}$ < $C{O}_2$ < $CO$
• B. $C{O}_2$ < $C{O}_3^{2-}$ < $CO$
• C. $CO$ < $C{O}_2$ <$C{O}_3^{2-}$
• D. $CO$ < $C{O}_2$ < $C{O}_3^{2-}$

Answer 1

The correct option is C $CO$ < $C{O}_2$ <$C{O}_3^{2-}$

$Bondlength$ $\propto \frac{1}{Bondorder}$

Bond order of $CO$ = 3

Bond order of $C{O}_2$ = 2

$Bondorder=\frac{No.ofbondsbetweentwoatomsinallpossiblestructures}{No.ofresonatingstructures}$


Bond order of $C{O}_3^{2-}$ = $\frac{4}{3}$ = 1.33

So the order of bond length is $CO$ < $C{O}_2$ < $C{O}_3^{2-}$