Question

The correct statement for the following structures is 

• A. 1, 2 and 3 are resonance structures
• B. 1 and 2 are resonance structures, whereas 3 is an isomer of 1 and 2
• C. 1 and 3 are resonance structures, whereas 2 is an isomer of 1 and 3
• D. 1, 2 and 3 are constitutional isomers

Hint:

Resonance structures differ only in the placement of electrons, whereas isomers have different connectivity or structures.

Answer 1

The Correct Option is D

To solve this question, we need to identify the relationship between the three given structures: 1, 2, and 3. The task is to determine whether they are resonance structures or constitutional isomers.

Let's analyze each option:

1. 1, 2, and 3 are resonance structures: Resonance structures are different representations of the same molecule, having the same molecular formula, connectivity of atoms, and differing only in the arrangement of electrons. In resonance, there is no movement of atoms, only of electrons.
2. 1 and 2 are resonance structures, whereas 3 is an isomer of 1 and 2: This option suggests that structures 1 and 2 are resonance forms, and 3 is structurally different in terms of atom connectivity. This hypothesis needs further examination of structure connectivity.
3. 1 and 3 are resonance structures, whereas 2 is an isomer of 1 and 3: This suggests 1 and 3 have the same atomic connectivity but differ in electron arrangement, implying 2 has a different atomic arrangement.
4. 1, 2, and 3 are constitutional isomers: Constitutional isomers share the same molecular formula but differ in the connectivity of atoms.

Upon closer examination of the structures in the image:

• The connectivity of atoms in structures 1, 2, and 3 is different for each, implying a difference in how the atoms are bonded together. This confirms they are constitutional isomers, which are compounds having the same molecular formula but differing in the arrangement of atoms.
• None of the structures are different only in the position of electrons (as seen in resonance structures), as each structure has clear differences in the arrangement of atoms.

Conclusion: The correct answer is: "1, 2 and 3 are constitutional isomers."