JEE Advanced 2022 Paper 2, Chemistry Section 1 Q5: Molecular Orbital Theory

JEE Advanced2022Paper 2Chemistry Section 1

Thermal decomposition of AgNO $_{3}$ produces two paramagnetic gases. The total number of electrons present in the antibonding molecular orbitals of the gas that has the higher number of unpaired electrons is _______.

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Solution

Thermal decomposition: $2 AgNO_{3} (s) Δ 2 Ag (s) + 2 NO_{2} (g) + O_{2} (g)$ .

Both NO $_{2}$ and O $_{2}$ are paramagnetic. NO $_{2}$ has 1 unpaired electron; O $_{2}$ has 2 unpaired electrons. Hence the relevant gas is O $_{2}$ .

Molecular orbital configuration of O $_{2}$ (16 electrons):

$σ_{1 s}^{2} σ_{1 s}^{*}^{2} σ_{2 s}^{2} σ_{2 s}^{*}^{2} σ_{2 p_{z}}^{2} π_{2 p_{x}}^{2} = π_{2 p_{y}}^{2} π_{2 p_{x}}^{*}^{1} = π_{2 p_{y}}^{*}^{1}$

Electrons in antibonding MOs: $σ_{1 s}^{*} (2) + σ_{2 s}^{*} (2) + π_{2 p_{x}}^{*} (1) + π_{2 p_{y}}^{*} (1) = 6$ .

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JEE Advanced 2022 Paper 2, Chemistry Section 1 Q5: Molecular Orbital Theory

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