If the magnetic moment of a dioxygen species is $1.73 \mathrm{~B.M}$, it may be:

(D) $\mathrm{O}_{2}^{-}$ or $\mathrm{O}_{2}^{+}$

(A) $\mathrm{O}_{2}, \mathrm{O}_{2}^{-}$ or $\mathrm{O}_{2}^{+}$

(B) $\mathrm{O}_{2}$ or $\mathrm{O}_{2}^{-}$

(C) $\mathrm{O}_{2}+\mathrm{O}_{2}^{+}$

JEE Main · 2020 · 09 Jan 2020 · Shift 1 · Coordination Compounds

If the magnetic moment of a dioxygen species is

1.73 B.M

, it may be:

(A) $O_{2}, O_{2}^{-}$ or $O_{2}^{+}$
(B) $O_{2}$ or $O_{2}^{-}$
(C) $O_{2} + O_{2}^{+}$
(D) $O_{2}^{-}$ or $O_{2}^{+}$ ✓ Correct

Answer: (D)

Solution

A moment of

1.73

BM corresponds, through

μ = n (n + 2)

, to exactly one unpaired electron. Neutral

O_{2}

carries two unpaired electrons in its

π^{*}

orbitals, so it is ruled out. Removing one electron to form

O_{2}^{+}

or adding one to form

O_{2}^{-}

each leaves a single unpaired electron, so the species must be either

O_{2}^{-}

O_{2}^{+}

JEE Main · 2020 · 09 Jan 2020 · Shift 1 · Single correct option

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