In which of the following, resonance is not possible?
1, 2
2, 4
3, 4
1, 4
2, 4
The explanation for the correct option:
Condition for resonance:
eg.
2. The Pi-bond is present at the alternate position to the atom bearing a negative charge.
eg.
3. A Pi-bond is present at the alternate position to the atom bearing a lone pair of electrons.
eg.
4. Pi- bond present at the alternate position to the atom bearing lone electron.
eg.
5. A Pi-bond is present at the alternate position to another Pi-bond.
eg.
Molecules (1) and (3) are obeying the above conditions.
The explanation for the incorrect option:
Molecules (2) and (4) are not obeying any of these conditions mentioned above.
Hence, (b) is the correct answer.