Question

Choose the correct option for following compounds:

• A. $I$ shows $\pi$ bond - $\sigma$ bond conjugation.
• B. $II$ shows $\pi$ bond - lone pair conjugation.
• C. $II$ shows lone pair - vacant orbital conjugation.
• D. $III$ shows $\pi$ bond - $\pi$ bond conjugation.

Answer 1

The correct option is C $II$ shows lone pair - vacant orbital conjugation.

Benzene molecule has 3 $\pi$ bonds which are in conjugation with each other. Therefore, it will show $\pi$ bond - $\pi$ bond type of conjugation.

In the molecule $II$, lone pair of $O$ atom conjugates with the vacant $p$ orbital of the $s{p}^2$ carbon. So, $II$ shows lone pair - vacant orbital conjugation.
In $III$ terminal $C{H}_2$ , carbon center has one negative charge which is in conjugation with $\pi$-bond or double bond.
So, it shows $\pi$ bond- Negative charge conjugation.