In which of the following options the species changes from paramagnetic to diamagnetic and bond order increases.
- \(N_2→N_{2}^{+}\)
- \(O_2→O_{2}^{+}\)
- \(NO→NO^+\)
- \(O_2→O^+\)
The Correct Option is C
Solution and Explanation
Solution:
- The molecular orbital theory explains that bond order is given by the formula:
\[
\text{Bond Order} = \frac{1}{2} \left( \text{Number of bonding electrons} - \text{Number of antibonding electrons} \right).
\]
- \( O_2 \) has a bond order of 2 and is paramagnetic because it has two unpaired electrons.
- When \( O_2 \) undergoes reduction to \( O_2^{2-} \), it gains two electrons, and its bond order decreases to 1.
- In the case of \( NO \), it is paramagnetic with a bond order of 2. When \( NO \) loses an electron to become \( NO^+ \), it has no unpaired electrons and becomes diamagnetic. Furthermore, the bond order increases to 2.5.
Thus, the process \( NO \rightarrow NO^+ \) satisfies both conditions of increasing bond order and changing from paramagnetic to diamagnetic.
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Concepts Used:
Molecular Orbital Theory
The Molecular Orbital Theory is a more sophisticated model of chemical bonding where new molecular orbitals are generated using a mathematical process called Linear Combination of Atomic Orbitals (LCAO).
Molecular Orbital theory is a chemical bonding theory that states that individual atoms combine together to form molecular orbitals. Due to this arrangement in MOT Theory, electrons associated with different nuclei can be found in different atomic orbitals. In molecular orbital theory, the electrons present in a molecule are not assigned to individual chemical bonds between the atoms. Rather, they are treated as moving under the influence of the atomic nuclei in the entire molecule.
