Chapter 14, Problem 54E

The diatomic molecule $\text{OH}$ exists in the gas phase. $\text{OH}$ plays an important part in combustion reactions and is a reactive oxidizing agent in polluted air. The bond length and bond energy have been measured to be $\text{97}\text{.06 pm}$ and $\text{424}\text{.7 kJ/mol}$ , respectively. Assume that the $\text{OH}$ molecule is analogous to the $\text{HF}$ molecule discussed in the chapter and that the $\text{MOs}$ result from the overlap of a ${\text{p}}_{\text{z}}$ orbital from oxygen and the $\text{1s}$ orbital of hydrogen (the $\text{O—H}$ bond lies along the $\text{z}$ axis).

1. Draw pictures of the sigma bonding and antibondingmolecular orbitals in $\text{OH}$ .
2. Which of the two $\text{MOs}$ has the greater hydrogen $\text{1s}$character?
3. Can the ${\text{2p}}_{\text{x}}$ orbital of oxygen form $\text{MOs}$ with the $\text{1s}$orbital of hydrogen? Explain.
4. Knowing that only the $\text{2p}$ orbitals of oxygen interact significantly with the $\text{1s}$ orbital of hydrogen, complete the $\text{MO}$ energy-level diagram for $\text{OH}$ . Place thecorrect number of electrons in the energy levels.



5. Estimate the bond order for $\text{OH}$ .
6. Predict whether the bond order of ${\text{OH}}^{\text{+}}$ is greaterthan, less than, or the same as that of $\text{OH}$ . Explain.