Question

The correct order of C - O bond length among $CO,C{O}_3^{2-},C{O}_2$ is:

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

Answer 1

The correct option is A

$CO<C{O}_2<C{O}_3^{2-}$

The higher the bond order, the shorter the $C–O$ bond length will be. $CO$ has a bond order of 3 (this is incorrect; it has a bond-order of at least 2.5). The carbonate anion has an average bond order of 1.33. Carbon dioxide has a bond order of 2. Hence, the order of increasing $C–O$ bond lengths is: $CO<C{O}_2<C{O}_3^{2-}$.