Identify the species having one $\pi$-bond and maximum number of canonical forms from the following:

JEE Main · 2021 · 25 Jul 2021 · Shift 2 · Chemical Bonding and Molecular Structure

Identify the species having one

π

-bond and maximum number of canonical forms from the following:

(A) $SO_{2}$
(B) $CO_{3}^{2 -}$ ✓ Correct
(C) $O_{2}$
(D) $SO_{3}$

Answer: (B)

Solution

SO₂ has one σ-bond and one π-bond between sulfur and each oxygen (with resonance). The key is that SO₂ has the maximum number of canonical forms among the given options while having one π-bond. SO₂ can be represented by multiple resonance structures showing the delocalization of the π-electron system. CO₃²⁻ has more π-bonds distributed, O₂ has two π-bonds, and SO₃ has three equivalent resonance structures but different bonding. SO₂ fits the criteria of having one π-bond with maximum canonical forms.

JEE Main · 2021 · 25 Jul 2021 · Shift 2 · Single correct option

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JEE Main · 2021 · 25 Jul 2021 · Shift 2 · Chemical Bonding and Molecular Structure

Solution

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