JEE Main 2022 — General Organic Chemistry Question with Solution

In $\left[10\right]$-Annulene - the hydrogen atoms in the $1$ and $6$ position interfere with each other and force the molecule out of planarity

If this annulene with five cis double bonds were planar, each internal angle would be $144°$. Since a normal double bond has bond angle of $120°$, this would be from ideal. This compound can be made but it does not adopt a planar conformation and therefore is not aromatic even though it has ten $\mathrm{\pi }$ electrons.