Which one of the following molecules contain no $\pi$-bond?
Which one of the following molecules contain no $\pi$-bond?
$\mathrm{CO}_2$
$\mathrm{H}_2 \mathrm{O}$
$\mathrm{SO}_2$
$\mathrm{NO}_2$
Solution
All the molecules have $\mathrm{O}$ atom with lone pairs, but in $\mathrm{H}_2 \mathrm{O}$ the $\mathrm{H}$ atom has no vacant orbital for $\pi$ bonding. That's why it does not have any $\pi$ bond.
In all other given molecules, the central atom because of the presence of vacant orbitals is capable to farm $\pi$ bonds.