Question

Choose the correct statement with respect to the bond length of $CO$ and $C{O}^{+}$ :

• A. The bond length in $CO$ is $1.128\mathring{A}$ and $C{O}^{+}$ is $1.115\mathring{A}$ because during conversion of $CO$ to $C{O}^{+}$ , electron is removed from anti bonding orbital.
• B. The bond length in $CO$ is $1.115\mathring{A}$ and $C{O}^{+}$ is $1.128\mathring{A}$ because during conversion of $CO$ to $C{O}^{+}$ electron is removed from bonding orbital.
• C. During conversion of $CO$ to $C{O}^{+}$ bond length does not vary because bond order remain same.
• D. The bond length in $CO$ is $1.115\mathring{A}$ and $C{O}^{+}$ is $1.128\mathring{A}$ because bond order decreases during conversion of $CO$ to $C{O}^{+}$ .

Answer 1

Answer: (A)

Because of the greater difference in electronegativity between $C$ and $O$, the energy of the molecular orbitals in CO are in the following order,
${\sigma }_{1s}^2{\sigma }_{1s}^{\ast 2}{\sigma }_{2s}^2{\pi }_{2p_y}^2={\pi }_{2p_z}^2{\sigma }_{2p_z}^2{\sigma }_{2s}^{\ast 2}$
Bond order in $CO=\frac{1}{2}10-4=3$
When $CO$ is converted to $C{O}^{+}$, one electron is removed from antibonding molecular orbitals. Hence, the bond order in $C{O}^{+}$is greater than $CO$.